Photoelectric conversion layer, photoelectric conversion device and imaging device, and method for applying electric field thereto

ABSTRACT

A photoelectric conversion layer comprising a compound represented by the following formula (I): 
                         
wherein V 1 , V 2 , V 3  and V 4  each independently represents a hydrogen atom or a substituent.

FIELD OF THE INVENTION

The present invention relates to a photoelectric conversion layer, aphotoelectric conversion device having the photoelectric conversionlayer and a solid imaging device, and to a method for applying anelectric field thereto and an applied device.

BACKGROUND OF THE INVENTION

A photoelectric conversion layer is widely utilized in, for example,optical sensors and in particular, is suitably used as a solid imagingdevice (light receiving device) of imaging device (solid imaging device)such as a television camera. As materials of the photoelectricconversion layer which is used as the solid imaging device of imagingdevice, layers made of an inorganic material such as Si layers and a-Selayers are mainly used.

Conventional photoelectric conversion layers using such an inorganicmaterial layer do not have sharp wavelength dependency againstphotoelectric conversion layer characteristics. For that reason, as toan imaging device using a photoelectric conversion layer, imagingdevices of a three-plate structure in which a prism capable of resolvingincident light into three red, green and blue primary colors and threesheets of photoelectric conversion layer to be disposed behind the prismare the main current.

However, imaging devices of such a three-plate type structure inevitablybecome large in both the dimension and the weight from the standpoint ofstructure.

In order to realize miniaturization and weight reduction of the imagingdevice, a device which is not required to provide a spectral prism andwhich is of a single-plate structure made of one sheet of a lightreceiving device is desired. For example, imaging devices of a structurein which red, green and blue filters are disposed in a single-platelight receiving device are studied. Also, it is studied to use, as amaterial of the photoelectric conversion layer, an organic materialhaving such advantages that the kind and characteristic are diverse andthat a degree of freedom in the processing shape is large. Aphotoelectric conversion layer having enhanced photosensitivity(sensitivity) and a light receiving device using the same are describedin JP-A-2003-158254. According to JP-A-2003-158254, organic materialsare used as a p-type semiconductor and an n-type semiconductor. However,in the working examples of JP-A-2003-158254, there is described only anexample in which polymethylphenylsilane (PMPS) is used as a p-typeorganic material, an 8-hydroxyquinoline-aluminum complex (Alq3) is usedas an n-type organic material, and coumarin 6 as an organic dye is addedin an amount of 5.0 parts by weight based on 100 parts by weight of theforegoing PMPS. Furthermore, in the section regarding preferredembodiments in JP-A-2003-158254, it is merely described that the organicdye is preferably used in an amount of from 0.1 to 50 parts by weightbased on 100 parts by weight of the p-type or n-type organic materialwhich constitutes the photoelectric conversion layer. However,JP-A-2003-158254 does not describe that the organic dye is used as thep-type or n-type organic material.

Also, for the purpose of realizing miniaturization and weight reductionof the imaging device, JP-A-2003-234460 describes a stack typephotoelectric conversion layer with a low resolution is described as adevice which is not required to provide a spectral prism and which is ofa single-plate structure made of one sheet of light receiving device.JP-A-2003-234460 describes that, for example, a preferred stack typephotoelectric conversion layer is prepared by stacking a photoelectricconversion layer having a function to absorb light of a wavelength ofany one color of three primary colors of light, a photoelectricconversion layer having a function to absorb light of a wavelength ofone of other colors and a photoelectric conversion layer having afunction to absorb the remaining color and that in this way, a colorimage having high sensitivity and resolution can be obtained.

However, in the working examples of JP-A-2003-234460, there is describedmerely a photoelectric conversion layer in which a coumarin 6/polysilanelayer having photosensitivity over the whole of a blue region of notmore than 500 nm and a ZnPc/Alq3 layer having an absorption region innot only a red region but also a blue region are used as photoelectricconversion layers, thereby having photosensitivity only over the wholeof a substantially red region in the center of from 600 to 700 nm due tothe filter function of the coumarin 6/polysilane layer.

Furthermore, JP-A-2003-332551 describes a stack type photoelectricconversion layer similar to the foregoing JP-A-2003-234460. However,JP-A-2003-158254, JP-A-2003-234460 and JP-A-2003-332551 do not describethat the dye according to the invention gives a preferred performance.

SUMMARY OF THE INVENTION

An object of the invention is to provide a photoelectric conversionlayer, a photoelectric conversion device and an imaging device(preferably a color image sensor) each having high photoelectricconversion efficiency, a narrow half-value width of absorption andexcellent color reproducibility.

The problems of the invention can be solved by the following dissolutionmeans.

(1) A photoelectric conversion layer comprising at least one kind ofcompounds represented by the following formula (I).

In the formula (I), V₁, V₂, V₃ and V₄ each represents a hydrogen atom ora substituent.

(2) The photoelectric conversion layer as set forth in (1), wherein thephotoelectric conversion layer has a p-type semiconductor layer and ann-type semiconductor layer, and at least one of the p-type semiconductorlayer and the n-type semiconductor layer contains a compound representedby the formula (I) as set forth in (1).(3) The photoelectric conversion layer as set forth in (2), wherein abulk heterojunction structure layer containing a p-type semiconductorand an n-type semiconductor is provided as an interlayer between thep-type semiconductor layer and the n-type semiconductor layer.(4) The photoelectric conversion layer as set forth in (2), which has astructure having the number of a repeating structure of a pn junctionlayer formed of the p-type semiconductor layer and the n-typesemiconductor layer of 2 or more.(5) The photoelectric conversion layer as set forth in any one of (2) to(4), wherein all of the p-type semiconductor and the n-typesemiconductor are an organic semiconductor.(6) The photoelectric conversion layer as set forth in any one of (1) to(5), wherein the layer containing a compound represented by the formula(I) in the photoelectric conversion layer has a thickness of 30 nm ormore and not more than 300 nm.(7) The photoelectric conversion layer as set forth in any one of (2) to(6), wherein the p-type semiconductor or the n-type semiconductor in theincident light side is colorless.(8) A photoelectric conversion device comprising the photoelectricconversion layer as set forth in any one of (1) to (7).(9) A photoelectric conversion device comprising the photoelectricconversion layer as set forth in any one of (2) to (7) between one pairof electrodes.(10) An imaging device comprising the photoelectric conversion device asset forth in (8) or (9).(11) An imaging device comprising two or more stacked layers ofphotoelectric conversion layers, wherein at least one photoelectricconversion layer is the photoelectric conversion layer as set forth inany one of (1) to (7).(12) The imaging device as set forth in (11), wherein three or more ofthe photoelectric conversion layers are stacked, and the three layersare three layers of a blue photoelectric conversion layer, a greenphotoelectric conversion layer and a red photoelectric conversion layer.(13) The imaging device as set forth in (12), wherein when spectralabsorption maximum values of the blue photoelectric conversion layer,the green photoelectric conversion layer and the red photoelectricconversion layer as set forth in (12) are designated as λmax1, λmax2 andλmax3, respectively, the λmax1 is in the range of 400 nm or more and notmore than 500 nm, the λmax2 is in the range of 500 nm or more and notmore than 600 nm, and the λmax3 is in the range of 600 nm or more andnot more than 700 nm.(14) The imaging device as set forth in (12), wherein when spectralsensitivity maximum values of the blue photoelectric conversion layer,the green photoelectric conversion layer and the red photoelectricconversion layer as set forth in (12) are designated as Smax1, Smax2 andSmax3, respectively, the Smax1 is in the range of 400 nm or more and notmore than 500 nm, the Smax2 is in the range of 500 nm or more and notmore than 600 nm, and the Smax3 is in the range of 600 nm or more andnot more than 700 nm.(15) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 50% of thespectral maximum absorption of each of the blue photoelectric conversionlayer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is not more than 120nm.(16) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 50% of thespectral maximum sensitivity of each of the blue photoelectricconversion layer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is not more than 120nm.(17) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 80% of thespectral maximum absorption of each of the blue photoelectric conversionlayer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is 20 nm or more andnot more than 100 nm.(18) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 80% of thespectral maximum sensitivity of each of the blue photoelectricconversion layer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is 20 nm or more andnot more than 100 nm.(19) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 20% of thespectral maximum absorption of each of the blue photoelectric conversionlayer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is not more than 180nm.(20) The imaging device as set forth in (12), wherein a gap between ashortest wavelength and a longest wavelength exhibiting 20% of thespectral maximum sensitivity of each of the blue photoelectricconversion layer, the green photoelectric conversion layer and the redphotoelectric conversion layer as set forth in (12) is not more than 180nm.(21) The imaging device as set forth in (12), wherein a longestwavelength exhibiting 50% of the spectral maximum absorption of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer as set forth in (12) is from460 nm to 510 nm, from 560 nm to 610 nm and from 640 nm to 730 nm,respectively.(22) The imaging device as set forth in (12), wherein a longestwavelength exhibiting 50% of the spectral maximum sensitivity of theblue photoelectric conversion layer, the green photoelectric conversionlayer and the red photoelectric conversion layer as set forth in (12) isfrom 460 nm to 510 nm, from 560 nm to 610 nm and from 640 nm to 730 nm,respectively.(23) An imaging device having at least two electromagnetic waveabsorption/photoelectric conversion sites, at least one of these sitescomprising the photoelectric conversion layer as set forth in any one of(1), (4) to (7), (9) and (10).(24) The imaging device as set forth in (23), wherein at least twoelectromagnetic wave absorption/photoelectric conversion sites have astack type structure of at least two layers.(25) The imaging device as set forth in (24), wherein an upper layerthereof comprises a site capable of absorbing green light and undergoingphotoelectric conversion.(26) An imaging device having at least three electromagnetic waveabsorption/photoelectric conversion sites, at least one of these sitescomprising the photoelectric conversion layer as set forth in any one of(1), (4) to (7), (9) and (10).(27) The imaging device as set forth in (26), wherein an upper layerthereof comprises a site capable of absorbing green light and undergoingphotoelectric conversion.(28) The image device as set forth in (26) or (27), wherein at least twoelectromagnetic wave absorption/photoelectric conversion sites comprisean inorganic layer.(29) The imaging device as set forth in (28), wherein at least twoelectromagnetic wave absorption/photoelectric conversion sites areformed within a silicon substrate.(30) A method for applying an electric field of 10⁻² V/cm or more andnot more than 1×10¹⁰ V/cm to the photoelectric conversion layer as setforth in any one of claim 1 to 7, the photoelectric conversion device asset forth in claim 8 or 9, or the imaging device as set forth in any oneof (10) to (29).(31) A photoelectric conversion layer as applied by the method as setforth in (30).(32) A photoelectric conversion device as applied by the method as setforth in (30).(33) An imaging device as applied by the method as set forth in (30).

The photoelectric conversion layer, the photoelectric conversion deviceand the imaging device according to the invention have advantages suchas a narrow half-value width of absorption, excellent colorreproducibility, high photoelectric conversion efficiency and highdurability. In two-layer stack type and BGR three-layer stack type solidimaging devices, there are the following characteristic features inaddition to the foregoing advantages.

Because of a stacked structure, a moiré pattern is not generated,resolution is high because an optical low pass filter is not required,and color blur is not formed. Furthermore, a signal treatment is simple,and a pseudo signal is not generated. In addition, in the case of CMOS,mixing of pixels is easy, and partial reading is easy.

Since an aperture is 100% and a micro lens is not required, there is nolimitation in an exit pupil distance against camera lens, and there isno shading. Accordingly, the invention is suitable for lensinterchangeable cameras. On this occasion, it becomes possible to makethe lens thin.

Since a micro lens is not required, it becomes possible to seal a glassby filling with an adhesive. Thus, it is possible to make a package thinand increase the yield, resulting in a reduction of costs.

Since an organic dye is used, high sensitivity is obtained, an IR filteris not required, and a flare is lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional schematic view of one pixel of aphotoelectric conversion layer stacked imaging device of a BRRthree-layer stack according to the invention.

FIG. 2 is a cross-sectional schematic view of a preferred imaging deviceaccording to the invention.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   -   101: P well layer    -   102, 104, 106: High-concentration impurity region    -   103, 105, 107: MOS circuit    -   108: Gate insulating layer    -   109, 110: Insulating layer    -   111, 114, 116, 119, 121, 124: Transparent electrode layer    -   112, 117, 122: Electrode    -   113, 118, 123: Photoelectric conversion layer    -   110, 115, 120, 125: Transparent insulating layer    -   126: Light shielding layer    -   150: Semiconductor substrate

DETAILED DESCRIPTION OF THE INVENTION

In the invention, the following compounds can be used as the compoundrepresented by the formula (I). Though these compounds may be used asany of an organic p-type semiconductor (dye) or an organic n-typesemiconductor (dye), they are preferably used as an organic n-typesemiconductor (dye).

Next, the compound represented by the formula (I) according to theinvention will be described in detail.

In the invention, in the case where a specific portion is called“group”, it is meant that even when the subject portion may be notsubstituted by itself, it may be substituted with one or more kinds (tothe highest possible number) of substituents. For example, the term“alkyl group” means a substituted or unsubstituted alkyl group.Furthermore, any substituent may be used as the substituent which can beused in the compound according to the invention.

When such a substituent is designated as “W”, any substituent may beused as the substituent represented by W without particular limitations.Examples thereof include a halogen atom, an alkyl group (inclusive of acycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), analkenyl group (inclusive of a cycloalkenyl group and a bicycloalkenylgroup), an alkynyl group, an aryl group, a heterocyclic group, a cyanogroup, a hydroxyl group, a nitro group, a carboxyl group, an alkoxygroup, an aryloxy group, a silyloxy group, a heterocyclic oxy group, anacyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, anaryloxycarbonyloxy group, an amino group (inclusive of an anilinogroup), an ammonio group, an acylamino group, an aminocarbonylaminogroup, an alkoxycarbonylamino group, an aryloxycarbonylamino group, asulfamoylamino group, an alkyl- or arylsulfonylamino group, a mercaptogroup, an alkylthio group, an arylthio group, a heterocyclic thio group,a sulfamoyl group, a sulfo group, an alkyl- or arylsulfinyl group, analkyl- or arylsulfonyl group, an acyl group, an aryloxycarbonyl group,an alkoxycarbonyl group, a carbamoyl group, an aryl or heterocyclic azogroup, an imide group, a phosphino group, a phosphinyl group, aphosphinyloxy group, a phosphinylamino group, a phosphono group, a silylgroup, a hydrazino group, a ureido group, a boronic acid group(—B(OH)₂), a phosphato group (—OPO(OH)₂), a sulfato group (—OSO₃H), andother known substituents.

In more detail, W represents a halogen atom (for example, a fluorineatom, a chlorine atom, a bromine atom, and an iodine atom), an alkylgroup [which represents a linear, branched or cyclic substituted orunsubstituted alkyl group; examples of which include an alkyl group(preferably an alkyl group having from 1 to 30 carbon atoms, forexample, methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl,2-chloroethyl, 2-cyanoethyl, and 2-ethylhexyl), a cycloalkyl group(preferably a substituted or unsubstituted cycloalkyl group having from3 to 30 carbon atoms, for example, cyclohexyl, cyclopentyl, and4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably a substitutedor unsubstituted bicycloalkyl group having from 5 to 30 carbon atoms,namely a monovalent group resulting from eliminating one hydrogen atomfrom a bicycloalkane having from 5 to 30 carbon atoms, for example,bicyclo[1,2,2]heptan-2-yl and bicyclo[2,2,2]octan-3-yl), and a tricyclicstructure containing more cyclic structures; and though the term “alkylgroup” in the substituents as described hereunder (for example, an alkylgroup of an alkylthio group) represents an alkyl group having suchconcept, it also includes an alkenyl group and an alkynyl group], analkenyl group [which represents a linear, branched or cyclic substitutedor unsubstituted alkenyl group; and examples of which include an alkenylgroup (preferably a substituted or un-substituted alkenyl group havingfrom 2 to 30 carbon atoms, for example, vinyl, allyl, prenyl, geranyl,and oleyl), a cycloalkenyl group (preferably a substituted orunsubstituted cycloalkenyl group having from 3 to 30 carbon atoms,namely a monovalent group resulting from eliminating one hydrogen atomfrom a cycloalkene having from 3 to 30 carbon atoms, for example,2-cyclopenten-1-yl and 2-cyclohexen-1-yl), and a bicycloalkenyl group (asubstituted or unsubstituted bi-cycloalkenyl group, and preferably asubstituted or unsubstituted bicycloalkenyl group having from 5 to 30carbon atoms, namely a monovalent group resulting from eliminating onehydrogen atom from a bicycloalkene containing one double bond, forexample, bicyclo[2,2,1]hept-2-en-1-yl and bicyclo[2,2,2]oct-2-en-4-yl)],an alkynyl group (preferably a substituted or unsubstituted alkynylgroup having from 2 to 30 carbon atoms, for example, ethynyl, propargyl,and trimethylsilylethynyl), an aryl group (preferably a substituted orunsubstituted aryl group having from 6 to 30 carbon atoms, for example,phenyl, p-tolyl, naphthyl, m-chlorophenyl, ando-hexadecanoylaminophenyl), a heterocyclic group (preferably amonovalent group resulting from eliminating one hydrogen atom from a 5-or 6-membered substituted or unsubstituted aromatic or non-aromaticheterocyclic compound, and more preferably a 5- or 6-membered aromaticheterocyclic group having from 3 to 30 carbon atoms, for example,2-furyl, 2-thienyl, 2-pyrimidinyl, and 2-benzothiazolyl; andincidentally, a cationic heterocyclic group such as 1-methyl-2-pyridinioand 1-methyl-2-quinolinio may also be employed), a cyano group, ahydroxyl group, a nitro group, a carboxyl group, an alkoxy group(preferably a substituted or unsubstituted alkoxy group having from 1 to30 carbon atoms, for example, methoxy, ethoxy, isopropoxy, t-butoxy,n-octyloxy, and 2-methoxyethoxy), an aryloxy group (preferably asubstituted or unsubstituted aryloxy group having from 6 to 30 carbonatoms, for example, phenoxy, 2-methylphenoxy, 4-t-butylphenoxy,3-nitrophenoxy, and 2-tetradecanoylaminophenoxy), a silyloxy group(preferably a silyloxy group having from 3 to 20 carbon atoms, forexample, trimethylsilyloxy and t-butyldimethylsilyloxy), a heterocyclicoxy group (preferably a substituted or unsubstituted heterocyclic oxygroup having from 2 to 30 carbon atoms, for example,1-phenyltetrazol-5-oxy and 2-tetrahydropyranyloxy), an acyloxy group(preferably a formyloxy group, a substituted or unsubstitutedalkylcarbonyloxy group having from 2 to 30 carbon atoms, and asubstituted or unsubstituted arylcarbonyloxy group having from 6 to 30carbon atoms, for example, formyloxy, acetyloxy, pivaloyloxy,stearoyloxy, benzoyloxy, and p-methoxyphenylcarbonyloxy), a carbamoyloxygroup (preferably a substituted or unsubstituted carbamoyloxy grouphaving from 1 to 30 carbon atoms, for example, N,N-dimethylcarbamoyloxy,N,N-diethylcarbamoyloxy, morpholinocarbonyloxy,N,N-di-n-octylaminocarbonyloxy, and N-n-octylcarbamoyloxy), analkoxycarbonyloxy group (preferably a substituted or unsubstitutedalkoxycarbonyloxy group having from 2 to 30 carbon atoms, for example,methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, andn-octylcarbonyloxy), an aryloxycarbonyloxy group (preferably asubstituted or unsubstituted aryloxycarbonyloxy group having from 7 to30 carbon atoms, for example, phenoxycarbonyloxy,p-methoxyphenoxycarbonyloxy, and p-n-hexadecyloxyphenoxycarbonyloxy), anamino group (preferably an amino group, a substituted or unsubstitutedalkylamino group having from 1 to 30 carbon atoms, and a substituted orunsubstituted anilino group having from 6 to 30 carbon atoms, forexample, amino, methylamino, dimethylamino, anilino, N-methyl-anilino,and diphenylamino), an ammonio group (preferably an ammonio group and anammonio group which is substituted with a substituted or unsubstitutedalkyl group, an aryl group or a heterocyclic group each having from 1 to30 carbon atoms, for example, trimethylammonio, triethylammonio, anddiphenylmethylammonio), an acylamino group (preferably a formylaminogroup, a substituted or unsubstituted alkylcarbonylamino group havingfrom 1 to 30 carbon atoms, and a substituted or unsubstitutedarylcarbonylamino group having from 6 to 30 carbon atoms, for example,formylamino, acetylamino, pivaroylamino, lauroylamino, benzoylamino, and3,4,5-tri-n-octyloxyphenylcarbonylamino), an aminocarbonylamino group(preferably a substituted or unsubstituted aminocarbonylamino grouphaving from 1 to 30 carbon atoms, for example, carbamoylamino,N,N-dimethylaminocarbonylamino, N,N-diethylaminocarbonylamino, andmorpholinocarbonylamino), an alkoxycarbonylamino group (preferably asubstituted or unsubstituted alkoxycarbonyl-amino group having from 2 to30 carbon atoms, for example, methoxycarbonylamino, ethoxycarbonylamino,t-butoxycarbonylamino, n-octadecyloxycarbonylamino, andN-methyl-methoxycarbonylamino), an aryloxycarbonylamino group(preferably a substituted or unsubstituted aryloxycarbonylamino grouphaving from 7 to 30 carbon atoms, for example, phenoxycarbonylamino,p-chlorophenoxycarbonylamino, and m-n-octyloxyphenoxycarbonylamino), asulfamoylamino group (preferably a substituted or unsubstitutedsulfamoylamino group having from 0 to 30 carbon atoms, for example,sulfamoylamino, N,N-dimethylaminosulfonylamino, andN-n-octylaminosulfonylamino), an alkyl- or arylsulfonylamino group(preferably a substituted or unsubstituted alkylsulfonylamino grouphaving from 1 to 30 carbon atoms and a substituted or unsubstitutedarylsulfonylamino group having from 6 to 30 carbon atoms, for example,methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino,2,3,5-trichlorophenylsulfonylamino, and p-methylphenylsulfonylamino), amercapto group, an alkylthio group (preferably a substituted orunsubstituted alkylthio group having from 1 to 30 carbon atoms, forexample, methylthio, ethylthio, and n-hexadecylthio), an arylthio group(preferably a substituted or unsubstituted arylthio group having from 6to 30 carbon atoms, for example, phenylthio, p-chlorophenylthio, andm-methoxyphenylthio), a heterocyclic thio group (preferably asubstituted or unsubstituted heterocyclic thio group having from 2 to 30carbon atoms, for example, 2-benzothiazoylthio and1-phenyltetrazol-5-ylthio), a sulfamoyl group (preferably a substitutedor unsubstituted sulfamoyl group having from 0 to 30 carbon atoms, forexample, N-ethylsulfamoyl, N-(3-dodecyloxypropyl)sulfamoyl,N,N-di-methylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl, andN—(N′-phenylcarbamoyl)sulfamoyl), a sulfo group, an alkyl- orarylsulfinyl group (preferably a substituted or unsubstitutedalkylsulfinyl group having from 1 to 30 carbon atoms and a substitutedor unsubstituted arylsulfinyl group having from 6 to 30 carbon atoms,for example, methylsulfinyl, ethylsulfinyl, phenylsulfinyl, andp-methylphenylsulfinyl), an alkyl- or arylsulfonyl group (preferably asubstituted or unsubstituted alkylsulfonyl group having from 1 to 30carbon atoms and a substituted or unsubstituted arylsulfonyl grouphaving from 6 to 30 carbon atoms, for example, methylsulfonyl,ethylsulfonyl, phenylsulfonyl, and p-methylphenylsulfonyl), an acylgroup (preferably a formyl group, a substituted or unsubstitutedalkylcarbonyl group having from 2 to 30 carbon atoms, a substituted orunsubstituted arylcarbonyl group having from 7 to 30 carbon atoms, and asubstituted or unsubstituted heterocyclic carbonyl group having from 4to 30 carbon atoms where the carbon atom of the heterocyclic group isconnected to the carbonyl group, for example, acetyl, pivaloyl,2-chloroacetyl, stearoyl, benzoyl, p-n-octyloxyphenylcarbonyl,2-pyridylcarbonyl, and 2-furfurylcarbonyl), an aryloxycarbonyl group(preferably a substituted or unsubstituted aryloxycarbonyl group havingfrom 7 to 30 carbon atoms, for example, phenoxycarbonyl,o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, andp-t-butylphenoxycarbonyl), an alkoxycarbonyl group (preferably asubstituted or unsubstituted alkoxycarbonyl group having from 2 to 30carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl,t-butoxycarbonyl, and n-octadecyloxycarbonyl), a carbamoyl group(preferably a substituted or unsubstituted carbamoyl group having from 1to 30 carbon atoms, for example, carbamoyl, N-methylcarbamoyl,N,N-dimethylcarbamoyl, N,N-di-n-octylcarbamoyl, andN-(methylsulfonyl)carbamoyl), an aryl or heterocyclic azo group(preferably a substituted or unsubstituted aryl azo group having from 6to 30 carbon atoms and a substituted or unsubstituted heterocyclic azogroup having from 3 to 30 carbon atoms, for example, phenylazo,p-chlorophenylazo, and 5-ethylthio-1,3,4-thiadiazol-2-ylazo), an imidegroup (preferably N-succimide and N-phthalimide), a phosphino group(preferably a substituted or unsubstituted phosphino group having from 2to 30 carbon atoms, for example, dimethylphosphino, diphenylphosphino,and methylphenoxyphosphino), a phosphinyl group (preferably asubstituted or unsubstituted phosphinyl group having from 2 to 30 carbonatoms, for example, phosphinyl, dioctyloxyphosphinyl, anddiethoxyphosphinyl), a phosphinyloxy group (preferably a substituted orunsubstituted phosphinyloxy group having from 2 to 30 carbon atoms, forexample, diphenyloxyphosphinyloxy and dioctyloxyphosphinyloxy), aphosphinylamino group (preferably a substituted or unsubstitutedphosphinylamino group having from 2 to 30 carbon atoms, for example,dimethoxyphosphinylamino and dimethyl-aminophosphinylamino), a phosphogroup, a silyl group (preferably a substituted or unsubstituted silylgroup having from 3 to 30 carbon atoms, for example, trimethylsilyl,t-butyldimethylsilyl, and phenyldimethylsilyl), a hydrazino group(preferably a substituted or unsubstituted hydrazino group having from 0to 30 carbon atoms, for example, trimethylhydrazino), or a ureido group(preferably a substituted or unsubstituted ureido group, for example,N,N-dimethylureido).

Furthermore, two Ws may be taken together to form a ring (an aromatic ornon-aromatic hydrocarbon ring or a heterocyclic ring; and these ringscan be further combined with each other to form a polycyclic fused ring,for example, a benzene ring, a naphthalene ring, an anthracene ring, aphenanthrene ring, a fluorene ring, a triphenylene ring, a naphthacenering, a biphenyl ring, a pyrrole ring, a furan ring, a thiophene ring,an imidazole ring, an oxazole ring, a thiazole ring, a pyridine ring, apyrazine ring, a pyrimidine ring, a pyridazine ring, an indolizine ring,an indole ring, a benzofuran ring, a benzothiophene ring, anisobenzofuran ring, a quinolizine ring, a quinoline ring, a phthalazinering, a naphthylidine ring, a quinoxaline ring, a quinoxazoline ring, anisoquinoline ring, a carbazole ring, a phenanthridine ring, an acridinering, a phenanthroline ring, a thianthrene ring, a chromene ring, axanthene ring, a phenoxathine ring, a phenothiazine ring, and aphenazine ring).

With respect to the substituent W, ones containing a hydrogen atom maybe converted by eliminating the hydrogen atom and further substitutingwith the foregoing group. Examples of such substituents include a—CONHSO₂— group (a sulfonylcarbonyl group or a carbonylsulfamoyl group),a —CONHCO— group (a carbonylcarbamoyl group), and an —SO₂NHSO₂— group (asulfonylsulfamoyl group).

More specifically, there are enumerated an alkylcarbonylaminosulfonylgroup (for example, acetylaminosulfonyl), an arylcarbonylaminosulfonylgroup (for example, benzoylaminosulfonyl), an alkylsulfonylaminocarbonylgroup (for example, methylsulfonylaminocarbonyl), and anarylsulfonylaminocarbonyl group (for example,p-methylphenylsulfonylaminocarbonyl).

In the formula (I), V₁, V₂, V₃ and V₄ each represents a hydrogen atom ora substituent. As the substituent, the foregoing W can be employed.

V₁ and V₂ are each preferably an alkyl group, an aryl group, or aheterocyclic group, and those as shown in W are preferable. V₁ and V₂are each more preferably an aryl group or a heterocyclic group, andespecially preferably an aryl group. As the aryl group, a substituted orunsubstituted aryl group having from 6 to 30 carbon atoms (for example,phenyl, p-tolyl, p-t-butylphenyl, p-chlorophenyl, p-biphenyl,m-chlorophenyl, m-cyanophenyl, o-tolyl, and naphthyl) is preferable,with p-chlorophenyl and p-biphenyl being more preferable. Incidentally,though V₁ and V₂ may be the same or different, it is preferable that V₁and V₂ are the same.

V₃ and V₄ are each preferably a hydrogen atom. Incidentally, in order tosolubilize the compound represented by the formula (I) in an organicsolvent, each of V₃ and V₄ may be converted to a protective group whichis cleaved by heat, light, an acid, a base, or the like. Preferredexamples of the protective group include a t-butoxycarbonyl group. Acompound having such a protective group is called “latent pigment”.Incidentally, though V₃ and V₄ may be the same or different, it ispreferable that V₃ and V₄ are the same.

The compound represented by the formula (I) according to the inventionis preferably a compound represented by the following formula (II).

In the formula (II), V₅ and V₆ each represents a substituent; and m₁ andm₂ each independently represents an integer of from 0 to 5.

As the substituent represented by V₅ and V₆, the foregoing W can beenumerated. The substituent is preferably a halogen atom, a cyano group,an alkyl group, an aryl group, or a heterocyclic group, and morepreferably a chlorine atom, a cyano group, a methyl group, a t-butylgroup, a phenyl group, or a thienyl group. Incidentally, though V₅ andV₆ may be the same or different, it is preferable that V₅ and V₆ are thesame.

The compound represented by the formula (I) according to the inventioncan be used as any of a dye or a pigment. The case where the compoundrepresented by the formula (I) is used as a pigment is preferable. Inthis case, any particle size of the organic dye is employable. However,the particle size of the organic dye is preferably in the range of from1 to 1,000 nm, more preferably in the range of from 1 to 500 nm,especially preferably in the range of from 1 to 100 nm, and mostpreferably in the range of from 1 to 20 nm.

Specific examples of the compound represented by the formula (I) whichis preferably used in the invention will be given below, but it shouldnot be construed that the invention is limited thereto.

The compound represented by the formula (I) according to the inventionand its synthesis method are described in Seishiro Ito ed., Ganryo noJiten (Pigment Dictionary), pages 341 to 344, 2000, published by AsakuraPublishing Co., Ltd.

[Molecular Weight]

We have found that the compound represented by the formula (I) accordingto the invention has a preferred molecular weight range. The molecularweight is preferably 250 or more and not more than 1,200, morepreferably 280 or more and not more than 1,000, and especiallypreferably 280 or more and not more than 500. When the molecular weightof the organic dye compound according to the invention falls within theforegoing range, it has been found that not only an advantage that thefilm formation by vapor deposition of the photoelectric conversion layeror the like can be easily achieved is brought, but also photoelectricconversion efficiency of the resulting photoelectric conversion layer ishigh and excellent and scatterings in optical absorptance andphotoelectric conversion efficiency among pixels of an imaging deviceare small.

[Definition of Hydrophilicity/Hydrophobicity]

We have found that the compound represented by the formula (I) accordingto the invention has a preferred hydrophilicity/hydrophobicity range.The hydrophilicity/hydrophobicity is preferably 2 or more and not morethan 10, more preferably 3 or more and not more than 8, and especiallypreferably 4 or more and not more than 6 in terms of “Clog P”. When thehydrophilicity/hydrophobicity of the organic dye compound according tothe invention falls within the foregoing range, it has been found thatnot only an advantage that the film formation by vapor deposition of thephotoelectric conversion layer or the like can be easily achieved isbrought, but also photoelectric conversion efficiency of the resultingphotoelectric conversion layer is high and excellent and scatterings inoptical absorptance and photoelectric conversion efficiency among pixelsof an imaging device is small. Also, it has been found that when thehydrophilicity/hydrophobicity of the organic dye compound according tothe invention falls within the foregoing range, it has been found thatdurability of the resulting layer, especially durability under a highhumidity condition is improved.

Incidentally, the “Clog P” is employed as an index of thehydrophilicity/hydrophobicity of the compound. Usually, thehydrophilicity/hydrophobicity can be determined by octanol/waterdistribution coefficient (log P). Concretely, thehydrophilicity/hydrophobicity can be actually measured by a flaskshaking method as described in the following Document (1).

Document (1)

Structure-Activity-Relationship society of Japan, Toshio Fujita(representative) ed., Kagaku no Ryoiki (Journal of Japan Chemistry),Supplementary Volume No. 122, “Structure-Activity-Relationships ofDrugs: Guides for Drug Design and Studying of Action Mechanism”, NankodoCo., Ltd. (1979), Chapter 2, pages 43 to 203; especially, the flaskshaking method is described on pages 86 to 89.

In the case where the log P is 3 or more, since the measurement maypossibly be difficult, a model for calculating the log P can be used inthe invention. In the invention, the hydrophilicity/hydrophobicity canbe defined by using the log P by a calculated value (hereinafterreferred to as “Clog P”).

In the object of the invention, a calculated value of log P iscalculated by using a CLOGP program of Hansch-Leo (Daylight ChemicalInformation Systems, U.S.A.) (version: algorithm=4.01, fragmentdatabase=17(*3)). In the case where this software is not available, thepresent applicant will provide Clog P values with respect to all ofspecific compounds.

In the case where the organic dye compound according to the inventiontakes plural tautomers, the Clog P regarding each of these isomers canbe calculated. If at least one of these values falls within a specificrange, the subject compound falls within the preferred range of theinvention. Furthermore, in the case where the foregoing database of theprogram does not include a molecular fragment, the Clog P can bedetermined by compensating a data by actual measurement of the foregoinghydrophilicity/hydrophobicity. In the organic dye compound according tothe invention, the Clog P is calculated on the basis of the state at apH of 7.

[Potential]

We have further found that the compound represented by the formula (I)according to the invention has a preferred potential range. Thepotential is preferably 0.3 V or more and not more than 1.8 V (vs SCE),more preferably 0.5 V or more and not more than 1.5 V, and especiallypreferably 0.8 V or more and not more than 1.3 V in terms of oxidationpotential. The potential is preferably −2 V or more and not more than−0.5 V (vs SCE), more preferably −1.6 V or more and not more than −0.8V, and especially preferably −1.4 V or more and not more than −1 V interms of reduction potential.

When the organic dye compound according to the invention falls withinthe foregoing range, it has been found that not only an advantage thatphotoelectric conversion efficiency of the resulting photoelectricconversion layer is high, but also durability of the photoelectricconversion layer is improved.

For the measurement of the reduction potential and the oxidationpotential, various methods can be employed. The case of phasediscrimination second harmonic alternating current polarography ispreferable, and accurate values can be determined. Incidentally, themethod for measuring a potential by the foregoing phase discriminationsecond harmonic alternating current polarography is described in Journalof Imaging Science, Vol. 30, page 27 (1986).

[Fluorescence]

We have further found that the organic dye compound according to theinvention has a preferred range of each of fluorescent quantum yield andfluorescent life. The fluorescent quantum yield is preferably 0.1 ormore and not more than 1, more preferably 0.5 or more and not more than1, and especially preferably 0.8 or more and not more than 1. Thefluorescent life is preferably 10 ps or more, more preferably 40 ps ormore, and especially preferably 160 ps or more. Though there is no upperlimit in the fluorescent life, the fluorescent life is preferably notmore than 1 ms.

When each of the each of fluorescent quantum yield and the fluorescentlife falls within the foregoing range, it has been found that not onlyan advantage that photoelectric conversion efficiency of the resultingphotoelectric conversion layer is high, but also durability of thephotoelectric conversion layer is improved.

The fluorescent quantum yield can be measured by a method as describedin JP-A-63-138341. This method will be hereunder described. That is, thefluorescent quantum yield of a dye in a layer can be basically measuredby the same method as in the case of a luminescent quantum yield of asolution. Usually, the fluorescent quantum yield can be determinedthrough relative measurement for comparing an intensity of incidentlight in a fixed optical orientation and a luminous intensity of asample by referring to a standard sample having a known absolute quantumyield (for example, Rhodamine B, quinine sulfate, and9,10-diphenylanthracene). This relative measurement method is describedin, for example, C. A. Parker and W. T. Rees, Analyst, 1960, Vol. 85,page 587. In the invention, though the fluorescent quantum yield may bea value in any of a solution state or a layer state, it is preferably avalue in a layer state.

The fluorescent life of the organic dye compound according to theinvention can be measured by a method as described in Tadaaki Tani,Takeshi Suzumoto, Klaus Kemnitz and Keitaro Yoshihara, The Journal ofPhysical Chemistry, 1992, Vol. 96, page 2778.

[Organic Layer]

An organic layer (organic film) in the invention will be hereunderdescribed. An electromagnetic wave absorption/photoelectric conversionsite made of an organic layer according to the invention comprises anorganic layer which is interposed between one pair of electrodes. Theorganic layer is formed by superposing or mixing a site for absorbingelectromagnetic waves, a photoelectric conversion site, an electrontransport site, a hole transport site, an electron blocking site, a holeblocking site, a crystallization preventing site, an electrode, aninterlaminar contact improving site, and so on.

It is preferable that the organic layer contains an organic p-typecompound or an organic n-type compound.

It is preferable that the organic layer contains an organic p-typesemiconductor (compound) and an organic n-type semiconductor (compound),and any substance may be employed. Furthermore, though the organic layermay or may not have absorption in visible and infrared regions, it ispreferable that the organic layer uses at least one compound (organicdye) having absorption in a visible region. In addition, it is possibleto use a p-type compound and an n-type compound and add an organic dyeto each of these compounds.

In the case of a three-layer structure of p-type layer/bulkheterojunction layer/n-type layer, it is preferable that the p-type orn-type semiconductor (compound) in the incident light side is colorless.

The organic p-type semiconductor (compound) is an organic semiconductor(compound) having donor properties and refers to an organic compoundwhich is mainly represented by a hole transport organic compound andwhich has properties such that it is liable to provide an electron. Inmore detail, the organic p-type semiconductor refers to an organiccompound having a smaller ionization potential in two organic compoundswhen they are brought into contact with each other and used.Accordingly, with respect to the organic compound having donorproperties, any organic compound can be used so far as it is an electrondonating organic compound. Useful examples thereof include triarylaminecompounds, benzidine compounds, pyrazoline compounds, styrylaminecompounds, hydrazone compounds, triphenylmethane compounds, carbazolecompounds, polysilane compounds, thiophene compounds, phthalocyaninecompounds, cyanine compounds, merocyanine compounds, oxonol compounds,polyamine compounds, indole compounds, pyrrole compounds, pyrazolecompounds, polyarylene compounds, fused aromatic carbocyclic compounds(for example, naphthalene derivatives, anthracene derivatives,phenanthrene derivatives, tetracene derivatives, pyrene derivatives,perylene derivatives, and fluoranthene derivatives), and metal complexeshaving, as a ligand, a nitrogen-containing heterocyclic compound.Incidentally, the invention is not limited to these compounds, and asdescribed previously, an organic compound having a smaller ionizationpotential than that of an organic compound to be used as an n-typecompound (having acceptor properties) may be used as the organicsemiconductor having donor properties.

The organic n-type semiconductor (compound) is an organic semiconductor(compound) having acceptor properties and refers to an organic compoundwhich is mainly represented by an electron transport organic compoundand which has properties such that it is liable to accept an electron.In more detail, the organic n-type semiconductor refers to an organiccompound having a larger electron affinity in two organic compounds whenthey are brought into contact with each other and used. Accordingly,with respect to the organic compound having acceptor properties, anyorganic compound can be used so far as it is an electron acceptingorganic compound. Useful examples thereof include fused aromaticcarbocyclic compounds (for example, naphthalene derivatives, anthracenederivatives, phenanthrene derivatives, tetracene derivatives, pyrenederivatives, perylene derivatives, and fluoranthene derivatives), 5- to7-membered heterocyclic compounds containing a nitrogen atom, an oxygenatom or a sulfur atom (for example, pyridine, pyrazine, pyrimidine,pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine,cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline,tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole,benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole,purine, triazolopyridazine, triazolopyrimidine, tetrazaindene,oxadiazole, imidazopyridine, pyralidine, pyrrolopyridine,thiadiazolopyridine, dibenzazepine, and tribenzazepine), polyarylenecompounds, fluorene compounds, cyclopentadiene compounds, silylcompounds, and metal complexes having, as a ligand, anitrogen-containing heterocyclic compound. Incidentally, the inventionis not limited to these compounds, and as described previously, anorganic compound having a larger electron affinity than that of anorganic compound to be used as an organic compound having donorproperties may be used as the organic semiconductor having acceptorproperties.

Though any organic dye may be used as the organic dye which is used inthe organic layer, it is preferred to use a p-type organic dye or ann-type organic dye. Though any organic dye is useful, preferred examplesthereof include cyanine dyes, styryl dyes, hemicyanine dyes, merocyaninedyes (inclusive of zeromethinemerocyanine (simple merocyanine)),trinuclear merocyanine dyes, tetranuclear merocyanine dyes, rhodacyaninedyes, complex cyanine dyes, complex merocyanine dyes, alopolar dyes,oxonol dyes, hemioxonol dyes, squarylium dyes, croconium dyes,azamethine dyes, coumarin dyes, arylidene dyes, anthraquinone dyes,triphenylmethane dyes, azo dyes, azomethine dyes, spiro compounds,metallocene dyes, fluorenone dyes, flugide dyes, perylene dyes,phenazine dyes, phenothiazine dyes, quinone dyes, indigo dyes,diphenylmethane dyes, polyene dyes, acridine dyes, acridinone dyes,diphenylamine dyes, quinacridone dyes, quinophthalone dyes, phenoxazinedyes, phthaloperylene dyes, dioxane dyes, porphyrin dyes, chlorophylldyes, phthalocyanine dyes, metal complex dyes, and fused aromaticcarbocyclic compounds (for example, naphthalene derivatives, anthracenederivatives, phenanthrene derivatives, tetracene derivatives, pyrenederivatives, perylene derivatives, and fluoranthene derivatives). In thecase where the compound represented by the foregoing formula (I) is usedas an organic dye, this compound can be used together with the foregoingdye.

As the color imaging device which is one of the objects of theinvention, there may be the case where a methine dye having a highdegree of freedom for adjusting the absorption wavelength, such ascyanine dyes, styryl dyes, hemicyanine dyes, merocyanine dyes,trinuclear merocyanine dyes, tetranuclear merocyanine dyes, rhodacyaninedyes, complex cyanine dyes, complex merocyanine dyes, alopolar dyes,oxonol dyes, hemioxonol dyes, squarylium dyes, croconium dyes, andazamethine dyes, gives adaptability to the wavelength.

Details of such methine dyes are described in the following dyedocuments.

[Dye Documents]

F. M. Harmer, Heterocyclic Compounds—Cyanine Dyes and Related Compounds,John Wiley & Sons, New York and London, 1964; D. M. Sturmer,Heterocyclic Compounds—Special topics in heterocyclic chemistry, Chapter18, Paragraph 14, pages 482 to 515, John Wiley & Sons, New York andLondon, 1977; Rodd's Chemistry of Carbon Compounds, 2nd Ed., Vol. IV,Part B, 1977, Chapter 15, pages 369 to 422, Elsevier Science PublishingCompany Inc., New York; and so on.

In addition, dyes as described in Research Disclosure (RD) 17643, pages23 to 24; RD 187716, page 648, right-hand column to page 649, right-handcolumn; RD 308119, page 996, right-hand column to page 998, right-handcolumn; and European Patent No. 0565096A1, page 65, lines 7 to 10 can bepreferably used. Furthermore, dyes having a partial structure or astructure represented by a formula or a specific example, as describedin U.S. Pat. No. 5,747,236 (in particular, pages 30 to 39), U.S. Pat.No. 5,994,051 (in particular, pages 32 to 43), and U.S. Pat. No.5,340,694 (in particular, pages 21 to 58, with proviso that in the dyesrepresented by (XI), (XII) and (XIII), the number of each of n₁₂, n₁₅,n₁₇ and n₁₈ is not limited and is an integer of 0 or more (preferablynot more than 4)) can be preferably used, too.

Next, the metal complex compound will be described. The metal complexcompound is a metal complex having a ligand containing at least one of anitrogen atom, an oxygen atom and a sulfur atom as coordinated to ametal. Though a metal ion in the metal complex is not particularlylimited, it is preferably a beryllium ion, a magnesium ion, an aluminumion, a gallium ion, a zinc ion, an indium ion, or a tin ion; morepreferably a beryllium ion, an aluminum ion, a gallium ion, or a zincion; and further preferably an aluminum ion or a zinc ion. As the ligandwhich is contained in the metal complex, there are enumerated variousknown ligands. Examples thereof include ligands as described in H.Yersin, Photochemistry and Photophysics of Coordination Compounds,Springer-Verlag, 1987; and Akio Yamamoto, OrganometallicChemistry—Principles and Applications, Shokabo Publishing Co., Ltd.,1982.

The foregoing ligand is preferably a nitrogen-containing heterocyclicligand (having preferably from 1 to 30 carbon atoms, more preferablyfrom 2 to 20 carbon atoms, and especially preferably from 3 to 15 carbonatoms, which may be a monodentate ligand or a bidentate or polydentateligand, with a bidentate ligand being preferable; and examples of whichinclude a pyridine ligand, a bipyridyl ligand, a quinolinol ligand, anda hydroxyphenylazole ligand (for example, a hydroxyphenylbenzimidazoleligand, a hydroxyphenylbenzoxazole ligand, and a hydroxyphenylimidazoleligand), an alkoxy ligand (having preferably from 1 to 30 carbon atoms,more preferably from 1 to 20 carbon atoms, and especially preferablyfrom 1 to 10 carbon atoms, examples of which include methoxy, ethoxy,butoxy, and 2-ethylhexyloxy), an aryloxy ligand (having preferably from6 to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, andespecially preferably from 6 to 12 carbon atoms, examples of whichinclude phenyloxy, 1-naphthyloxy, 2-naphthyloxy,2,4,6-trimethylphenyloxy, and 4-biphenyloxy), an aromatic heterocyclicoxy ligand (having preferably from 1 to 30 carbon atoms, more preferablyfrom 1 to 20 carbon atoms, and especially preferably from 1 to 12 carbonatoms, examples of which include pyridyloxy, pyrazyloxy, pyrimidyloxy,and quinolyloxy), an alkylthio ligand (having preferably from 1 to 30carbon atoms, more preferably from 1 to 20 carbon atoms, and especiallypreferably from 1 to 12 carbon atoms, examples of which includemethylthio and ethylthio), an arylthio ligand (having preferably from 6to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, andespecially preferably from 6 to 12 carbon atoms, examples of whichinclude phenylthio), a heterocyclic substituted thio ligand (havingpreferably from 1 to 30 carbon atoms, more preferably from 1 to 20carbon atoms, and especially preferably from 1 to 12 carbon atoms,examples of which include pyridylthio, 2-benzimidazolylthio,2-benzoxazolylthio, and 2-benzothiazolylthio), or a siloxy ligand(having preferably from 1 to 30 carbon atoms, more preferably from 3 to25 carbon atoms, and especially preferably from 6 to 20 carbon atoms,examples of which include a triphenyloxy group, a triethoxysiloxy group,and a triisopropylsiloxy group); more preferably a nitrogen-containingheterocyclic ligand, an aryloxy ligand, an aromatic heterocyclic oxyligand, or a siloxy ligand; and further preferably a nitrogen-containingheterocyclic ligand, an aryloxy ligand, or a siloxy ligand.

As the organic dye which is used in the invention, quinacridone dyes anddiketopyrropyrrole dyes are especially preferable.

In particular, the case where the quinacridone dye (preferably aquinacridone derivative represented by the formula (I) as described inJapanese Patent Application No. 2005-65395) is used as a p-type dye andthe diketopyrropyrrole dye (preferably a compound represented by theforegoing formula (I)) is used as an n-type dye is preferable.

The layer which the organic dye forms may be in any of an amorphousstate, a liquid crystal state or a crystal state. In the case where thelayer is used in a crystal state, it is preferred to use a pigment.

A blending ratio of the p-type organic semiconductor and the n-typeorganic semiconductor in the interlayer of the photoelectric conversionlayer can be properly set up within the range of from 0.1/99.9 to99.9/0.1 in terms of a weight ratio.

[Electron Transport Material]

In the photoelectric conversion layer according to the invention, wehave found that the case where the organic material having electrontransport properties (n-type compound) has an ionization potential oflarger than 6.0 eV is preferable and that the case where the organicmaterial having electron transport properties (n-type compound) isrepresented by the following formula (X) is more preferable.

Formula (X)L-(A)_(m)

In the formula (X), A represents a heterocyclic group having two or morearomatic hetero rings fused therein; the heterocyclic groups representedby A may be the same or different; m represents an integer of 2 or more(preferably from 2 to 8); and L represents a connecting group.

Incidentally, details and preferred ranges of such organic materialshaving electron transport properties are described in detail in JapanesePatent Application No. 2004-082002.

When such an organic material having electron transport properties isused, the photoelectric conversion efficiency of the resultingphotoelectric conversion layer becomes remarkably high.

[Orientation Control of Organic Layer]

In the invention, the orientation control as described below can beapplied.

In the invention, it is preferable that the orientation of the organiccompound has an order as compared with random orientation. Unless theorientation is random, the degree of order may be low or high. Theorientation of the organic compound is preferably in a high order.

In the photoelectric conversion layer having a layer of a p-typesemiconductor and a layer of an n-type semiconductor (preferably a mixedor dispersed (bulk heterojunction structure) layer) between one pair ofelectrodes, the case of a photoelectric conversion layer which ischaracterized by containing an orientation-controlled organic compoundin at least one of the p-type semiconductor and the n-type semiconductoris preferable; and the case of a photoelectric conversion layer which ischaracterized by containing an orientation-controlled (orientationcontrollable) organic compound in both the p-type semiconductor and then-type semiconductor is more preferable.

As the organic compound which is used in the organic layer of thephotoelectric conversion device, an organic compound having aπ-conjugated electron is preferably used. The π-electron plane is notvertical to a substrate (electrode substrate) and is oriented at anangle close to parallel to the substrate as far as possible. The angleagainst the substrate is preferably 0° or more and not more than 80°,more preferably 0° or more and not more than 60°, further preferably 0°or more and not more than 40°, still further preferably 0° or more andnot more than 20°, especially preferably 0° or more and not more than10°, and most preferably 0° (namely, in parallel to the substrate).

As described previously, it is only required that even a part of thelayer of the orientation-controlled organic compound is contained overthe whole of the organic layer. A proportion of theorientation-controlled portion to the whole of the organic layer ispreferably 10% or more, more preferably 30% or more, further preferably50% or more, still further preferably 70% or more, especially preferably90% or more, and most preferably 100%. In the photoelectric conversionlayer, by controlling the orientation of the organic compound of theorganic layer, the foregoing state compensates a drawback that theorganic layer in the photoelectric conversion layer has a short carrierdiffusion length, thereby improving the photoelectric conversionefficiency.

The orientation of the organic compound can be controlled by selectingthe substrate, adjusting the vapor deposition condition, and othermeans. For example, there is enumerated a method in which the surface ofthe substrate is subjected to a rubbing treatment, thereby impartinganisotropy to the organic compound to be grown thereon. However, thestructure relying upon a crystal as the substrate is observed only inthe thickness of at most ten-odd layers, and when the layer thicknessbecomes thick, a bulk crystal structure is taken. In the photoelectricconversion device according to the invention, in order to increase theoptical absorptance, the case where the layer thickness is 100 nm ormore (100 layers or more as the molecule) is preferable. In such case,the orientation must be controlled by utilizing a mutual action amongthe organic compounds in addition to the substrate.

Any force of the mutual action among the organic compounds isemployable. Examples of an intermolecular force include a van der Waalsforce (in more detail, the van der Waals force can be expressed whileclassifying into an orientation force to work between a permanent dipoleand a permanent dipole, an induction force to work between a permanentdipole and an induced dipole, and a dispersion force to work between atemporary dipole and an induced dipole), a charge transfer force (CT), aCoulomb's force (electrostatic force), a hydrophobic bond force, ahydrogen bond force, and a coordination bond force. These bond forcescan be used singly or in an arbitrary combination of plural bond forces.

Of these, a van der Waals force, a charge transfer force, a Coulomb'sforce, a hydrophobic bond force, and a hydrogen bond force arepreferable; a van der Waals force, a Coulomb's force, and a hydrogenbond force are more preferable; a van der Waals force and a Coulomb'sforce are especially preferable; and a van der Waals force is the mostpreferable.

In the invention, as the mutual action among the organic compounds, acovalent bond or a coordination bond can also be employed. The casewhere the organic compounds are connected to each other via a covalentbond is preferable (incidentally, the coordination bond force can beconsidered as one coordination bond force of the intermolecular force).In such case, the covalent bond or the coordination bond may be formedin advance or may be formed during the process for forming an organiclayer.

With respect to the foregoing intermolecular force and covalent bond, itis preferable that the orientation of an organic compound is controlledby using an intermolecular force.

Energy of the attraction of the intermolecular force is preferably 15kJ/mole or more, more preferably 20 kJ/mole or more, and especiallypreferably 40 kJ/mole or more. Though there is no particular upperlimit, the energy is preferably not more than 5,000 kJ/mole, and morepreferably not more than 1,000 kJ/mole.

Furthermore, there can be employed a method in which dielectricanisotropy or polarization is imparted to an organic compound and anelectric field is applied during the growth to orient the molecule.

In the case where the orientation of an organic compound is controlled,it is more preferable that the heterojunction plane (for example, a pnjunction plane) is not in parallel to a substrate. In this case, it ispreferable that the heterojunction plane is not in parallel to thesubstrate (electrode substrate) but is oriented at an angle close toverticality to the substrate as far as position. The angle to thesubstrate is preferable 0° or more and not more than 90°, morepreferably 30° or more and not more than 90°, further preferably 50° ormore and not more than 90°, still further preferably 70° or more and notmore than 90°, especially preferably 80° or more and not more than 90°,and most preferably 90° (namely, vertical to the substrate).

As described previously, it is only required that even a part of thelayer of the heterojunction plane-controlled organic compound iscontained over the whole of the organic layer. A proportion of theorientation-controlled portion to the whole of the organic layer ispreferably 10% or more, more preferably 30% or more, further preferably50% or more, still further preferably 70% or more, especially preferably90% or more, and most preferably 100%. In such case, the area of theheterojunction plane in the organic layer increases and the amount of acarrier such as an electron as formed on the interface, a hole, and apair of an electron and a hole increases so that it is possible toimprove the photoelectric conversion efficiency.

As examples of concrete drawings of a photoelectric conversion layerhaving the foregoing heterojunction layer (plane), ones described inFIGS. 1 to 8 of JP-A-2003-298152 are applicable.

In the light of the above, in the photoelectric conversion layer inwhich the orientation of the organic compound on both the heterojunctionplane and the π-electron plane is controlled, in particular, it ispossible to improve the photoelectric conversion efficiency andtherefore, such is preferable. Especially, the case in which a bulkheterojunction structure is taken can be preferably employed.

(Formation Method of Organic Layer)

A layer containing such an organic compound is subjected to filmformation by a dry film formation method or a wet film formation method.Specific examples of the dry film formation method include physicalvapor phase epitaxy methods such as a vacuum vapor deposition method, asputtering method, an ion plating method, and an MBE method and CVDmethods such as plasma polymerization. Examples of the wet filmformation method include a casting method, a spin coating method, adipping method, and an LB method.

In the case of using a high molecular compound in at least one of thep-type semiconductor (compound) and the n-type semiconductor (compound),it is preferable that the film formation is achieved by a wet filmformation method which is easy for the preparation. In the case ofemploying a dry film formation method such as vapor deposition, the useof a high molecular compound is difficult because of possible occurrenceof decomposition. Accordingly, its oligomer can be preferably usedinstead of that.

On the other hand, in the case of using a low molecular compound, a dryfilm formation method is preferably employed, and a vacuum vapordeposition method is especially preferably employed. In the vacuum vapordeposition method, a method for heating a compound such as a resistanceheating vapor deposition method and an electron beam heating vapordeposition method, the shape of a vapor deposition source such as acrucible and a boat, a degree of vacuum, a vapor deposition temperature,a substrate temperature, a vapor deposition rate, and the like are abasic parameter. In order to achieve uniform vapor deposition, it ispreferable that the vapor deposition is carried out while rotating thesubstrate. A high degree of vacuum is preferable. The vacuum vapordeposition is carried out at a degree of vacuum of not more than 10⁻⁴Torr, preferably not more than 10⁻⁶ Torr, and especially preferably notmore than 10⁻⁸ Torr. It is preferable that all steps at the time ofvapor deposition are carried out in vacuo. Basically, the vacuum vaporposition is carried out in such a manner that the compound does not comeinto direct contact with the external oxygen and moisture. The foregoingconditions of the vacuum vapor deposition must be strictly controlledbecause they affect crystallinity, amorphous properties, density,compactness, and so no. It is preferably employed to subject the vapordeposition rate to PI or PID control using a layer thickness monitorsuch as a quartz oscillator and an interferometer. In the case of vapordepositing two or more kinds of compounds at the same time, a co-vapordeposition method, a flash vapor deposition method and so on can bepreferably employed.

[Definition of Absorption Wavelength]

We have found that the organic dye compound according to the inventionhas a preferred range of each of spectral absorption wavelength andspectral sensitivity regions.

In the invention, a BGR photoelectric conversion layer with good colorreproducibility, namely a photoelectric conversion device having threelayers of a blue photoelectric conversion layer, a green photoelectricconversion layer and a red photoelectric conversion layer stackedthereon can be preferably used. The case where each of the photoelectricconversion layers has the following spectral absorption and/or spectralsensitivity characteristics is preferable.

When spectral absorption maximum values are respectively designated asλmax1, λmax2 and λmax3 in the order of BGR and spectral sensitivitymaximum values are respectively designated as Smax1, Smax2 and Smax3 inthe order of BGR, the πmax1 and the Smax1 are each preferably in therange of 400 nm or more and not more than 500 nm, more preferably in therange of 420 nm or more and not more than 480 nm, and especiallypreferably in the range of 430 nm or more and not more than 470 nm; theλmax2 and the Smax2 are each preferably in the range of 500 nm or moreand not more than 600 nm, more preferably in the range of 520 nm or moreand not more than 580 nm, and especially preferably in the range of 530nm or more and not more than 570 nm; and the λmax3 and the Smax3 areeach preferably in the range of 600 nm or more and not more than 700 nm,more preferably in the range of 620 nm or more and not more than 680 nm,and especially preferably in the range of 630 nm or more and not morethan 670 nm.

Furthermore, in the case of the photoelectric conversion layer accordingto the invention takes a stacked structure of three or more layers, agap between a shortest wavelength and a longest wavelength exhibiting50% of each of the spectral maximum absorption of each of λmax1, λmax2and λmax3 and the spectral maximum sensitivity of each of Smax1, Smax2and Smax3 is preferably not more than 120 nm, more preferably not morethan 100 nm, especially preferably not more than 80 nm, and mostpreferably not more than 70 nm.

Furthermore, in the case of the photoelectric conversion layer accordingto the invention takes a stacked structure of three or more layers, agap between a shortest wavelength and a longest wavelength exhibiting80% of each of the spectral maximum absorption of each of λmax1, λmax2and λmax3 and the spectral maximum sensitivity of each of Smax1, Smax2and Smax3 is preferably 20 nm or more and preferably not more than 100nm, more preferably not more than 80 nm, and especially preferably notmore than 50 nm.

Furthermore, in the case of the photoelectric conversion layer accordingto the invention takes a stacked structure of three or more layers, agap between a shortest wavelength and a longest wavelength exhibiting20% of each of the spectral maximum absorption of each of λmax1, λmax2and λmax3 and the spectral maximum sensitivity of each of Smax1, Smax2and Smax3 is preferably not more than 180 nm, more preferably not morethan 150 nm, especially preferably not more than 120 nm, and mostpreferably not more than 100 nm.

Furthermore, in the long wavelength sides of λmax1, λmax2 and λmax3 andSmax1, Smax2 and Smax3, a longest wavelength exhibiting a spectralabsorptance of 50% of each of the spectral maximum absorption of each ofλmax1, λmax2 and λmax3 and the spectral maximum sensitivity of each ofSmax1, Smax2 and Smax3 is preferably 460 nm or more and not more than510 nm for λmax1 and Smax1, 560 nm or more and not more than 610 nm forλmax2 and Smax2 and 640 nm or more and not more than 730 nm for λmax3and Smax3, respectively.

When the spectral absorption wavelength and spectral sensitivity regionranges of the compound according to the invention fall within theforegoing ranges, it is possible to improve the color reproducibility ofcolor images obtained by the imaging device.

[Definition of Layer Thickness of Organic Dye Layer]

In the case of using the photoelectric conversion layer according to theinvention as a color imaging device (image sensor), for the purposes ofimproving the photoelectric conversion efficiency and further improvingcolor separation without passing excessive light through a lower layer,an optical absorptance of the organic dye layer of each of B, G and Rlayers is preferably set up at 50% or more, more preferably 70% or more,especially preferably 90% (absorbance=1) or more, and most preferably99% or more. Accordingly, from the standpoint of optical absorption, itis preferable that the layer thickness of the organic dye layer is asthick as possible. However, taking into consideration a proportion forcontributing to the charge separation, the layer thickness of theorganic dye layer in the invention is preferably 30 nm or more and notmore than 300 nm, more preferably 50 nm or more and not more than 250nm, especially preferably 60 nm or more and not more than 200 nm, andmost preferably 80 nm or more and not more than 130 nm.

[Application of Voltage]

The case of applying voltage to the photoelectric conversion layeraccording to the invention is preferable in view of improving thephotoelectric conversion efficiency. Though any voltage is employable asthe voltage to be applied, necessary voltage varies with the layerthickness of the photoelectric conversion layer. That is, the larger anelectric field to be added in the photoelectric conversion layer, themore improved the photoelectric conversion efficiency is. However, evenwhen the same voltage is applied, the thinner the layer thickness of thephotoelectric conversion layer, the larger an electric field to beapplied is. Accordingly, in the case where the layer thickness of thephotoelectric conversion film is thin, the voltage to be applied may berelatively small. The electric field to be applied to the photoelectricconversion layer is preferably 10⁻² V/cm or more, more preferably 10V/cm or more, further preferably 1×10³ V/cm or more, especiallypreferably 1×10⁴ V/cm or more, and most preferably 1×10⁵ V/cm or more.Though there is no particular upper limit, when the electric field isexcessively applied, an electric current flows even in a dark place andtherefore, such is not preferable. The electric field is preferably notmore than 1×10¹⁰ V/cm, and more preferably not more than 1×10⁷ V/cm.

[General Requirements]

In the invention, the photoelectric conversion device is preferably aconstruction where at least two layers are stacked, more preferably aconstruction where three layers or four layers are stacked, andespecially preferably a construction where three layers are stacked.

In the invention, such a photoelectric conversion device can bepreferably used as an imaging device, and especially preferably as asolid imaging device. Furthermore, in the invention, the case wherevoltage is applied to the photoelectric conversion layer, thephotoelectric conversion device and the imaging device.

The case where the photoelectric conversion device according to theinvention has a photoelectric conversion layer having a stackedstructure in which a layer of the p-type semiconductor and a layer ofthe n-type semiconductor are disposed between one pair of electrodes ispreferable. Furthermore, the case where at least one of the p-typesemiconductor and the n-type semiconductor contains an organic compoundis preferable; and the case where both the p-type semiconductor and then-type semiconductor contain an organic compound is more preferable.

[Bulk Heterojunction Structure]

In the invention, the case containing a photoelectric conversion layer(photosensitive layer) having a p-type semiconductor layer and an n-typesemiconductor layer between one pair of electrodes, with at least one ofthe p-type semiconductor layer and the n-type semiconductor layer beingan organic semiconductor, and a bulk heterojunction structure layercontaining the p-type semiconductor and the n-type semiconductor as aninterlayer between these semiconductor layers is preferable. In suchcase, in the photoelectric conversion layer, by containing a bulkheterojunction structure in the organic layer, a drawback that theorganic layer has a short carrier diffusion length is compensated,thereby improving the photoelectric conversion efficiency.

Incidentally, the bulk heterojunction structure is described in detailin Japanese Patent Application No. 2004-080639.

[Tandem Structure]

In the invention, the case containing a photoelectric conversion layer(photosensitive layer) having a structure having the number of arepeating structure (tandem structure) of a pn junction layer formed ofthe p-type semiconductor layer and the n-type semiconductor layerbetween one pair of electrodes of 2 or more is preferable. Furthermore,a thin layer made of a conducting material may be inserted between theforegoing repeating structures. The conducting material is preferablysilver or gold, and most preferably silver. The number of the repeatingstructure (tandem structure) of a pn junction layer is not limited. Forthe purpose of enhancing the photoelectric conversion efficiency, thenumber of the repeating structure (tandem structure) of a pn junctionlayer is preferably 2 or more and not more than 100, more preferably 2or more and not more than 50, especially preferably 5 or more and notmore than 40, and most preferably 10 or more and not more than 30.

In the invention, though the semiconductor having a tandem structure maybe made of an inorganic material, it is preferably an organicsemiconductor, and more preferably an organic dye.

Incidentally, the tandem structure is described in detail in JapanesePatent Application No. 2004-079930.

[Stacked Structure]

As one preferred embodiment of the invention, in the case where voltageis not applied to the photoelectric conversion layer, it is preferablethat at least two photoelectric conversion layers are stacked. Thestacked imaging devices is not particularly limited, and all stackedimaging device which are used in this field are applicable. However, aBGR three-layer stacked structure is preferable. A preferred example ofthe BGR stacked structure is shown in FIG. 1.

Next, for example, the solid imaging device according to the inventionhas a photoelectric conversion layer as shown in this embodiment. Thesolid imaging device as shown in FIG. 1 is provided with a stack typephotoelectric conversion layer on a scanning circuit part. For thescanning circuit part, a construction in which an MOS transistor isformed on a semiconductor substrate for every pixel unit or aconstruction having CCD as an imaging device can be properly employed.

For example, in the case of a solid imaging device using an MOStransistor, a charge is generated in a photoelectric conversion layer byincident light which has transmitted through electrodes; the charge runsto the electrodes within the photoelectric conversion layer by anelectric field as generated between the electrodes by applying voltageto the electrodes; and the charge is further transferred to a chargeaccumulating part of the MOS transistor and accumulated in the chargeaccumulating part. The charge as accumulated in the charge accumulatingpart is transferred to a charge read-out part by switching of the MOStransistor and further outputted as an electric signal. In this way,full-color image signals are inputted in a solid imaging deviceincluding a signal processing part.

With respect to such a stacked imaging device, solid color imagingdevices represented by those described in FIG. 2 of JP-A-58-103165 andin FIG. 2 of JP-A-58-103166 and so on can also be applied.

With respect to the manufacturing process of the foregoing stack typeimaging device, preferably a three-layer stack type imaging device, amethod as described in JP-A-2002-83946 (see FIGS. 7 to 23 and paragraphs[0026] to [0038] of JP-A-2002-83946) can be applied.

(Photoelectric Conversion Device)

The photoelectric conversion device of a preferred embodiment accordingto the invention will be hereunder described.

The photoelectric conversion device according to the invention iscomprised of an electromagnetic wave absorption/photoelectric conversionsite and a charge accumulation of charge as generated by photoelectricconversion/transfer/and read-out site.

In the invention, the electromagnetic wave absorption/photoelectricconversion site has a stack type structure made of at least two layers,which is capable of absorbing each of blue light, green light and redlight and undergoing photoelectric conversion. A blue light absorbinglayer (B) is able to absorb at least light of 400 nm or more and notmore than 500 nm and preferably has an absorptance of a peak wavelengthin that wavelength region of 50% or more. A green light absorbing layer(G) is able to absorb at least light of 500 nm or more and not more than600 nm and preferably has an absorptance of a peak wavelength in thatwavelength region of 50% or more. A red light absorbing layer (R) isable to absorb at least light of 600 nm or more and not more than 700 nmand preferably has an absorptance of a peak wavelength in thatwavelength region of 50% or more. The order of these layers is notlimited. In the case of a three-layer stack type structure, orders ofBGR, BRG, GBR, GRB, RBG and RGB from the upper layer (light incidentside) are possible. It is preferable that the uppermost layer is G. Inthe case of a two-layer stack type structure, when the upper layer is anR layer, a BG layer is formed as the lower layer in the same planarstate; when the upper layer is a B layer, a GR layer is formed as thelower layer in the same planar state; and when the upper layer is a Glayer, a BR layer is formed as the lower layer in the same planar state.It is preferable that the upper layer is a G layer and the lower layeris a BR layer in the same planar state. In the case where two lightabsorbing layers are provided in the same planar state of the lowerlayer in this way, it is preferable that a filter layer capable ofundergoing color separation is provided in, for example, a mosaic stateon the upper layer or between the upper layer and the lower layer. Undersome circumstances, it is possible to provide a fourth or polynomiallayer as a new layer or in the same planar state.

In the invention, the charge accumulation/transfer/read-out site isprovided under the electromagnetic wave absorption/photoelectricconversion site. It is preferable that the electromagnetic waveabsorption/photoelectric conversion site which is the lower layer alsoserves as the charge accumulation/transfer/read-out site.

In the invention, the electromagnetic wave absorption/photoelectricconversion site is made of an organic layer or an inorganic layer or amixture of an organic layer and an inorganic layer. The organic layermay form a B/G/R layer or the inorganic layer may form a B/G/R layer. Itis preferable that the electromagnetic wave absorption/photoelectricconversion site is made of a mixture of an organic layer and aninorganic layer. In this case, basically, when the organic layer is madeof a single layer, the inorganic layer is made of a single layer or twolayers; and when the organic layer is made of two layers, the inorganiclayer is made of a single layer. When each of the organic layer and theinorganic layer is made of a single layer, the inorganic layer forms anelectromagnetic wave absorption/photoelectric conversion site of two ormore colors in the same planar state. It is preferable that the upperlayer is made of an organic layer which is constructed of a G layer andthe lower layer is made of an inorganic layer which is constructed of aB layer and an R layer in this order from the upper side. Under somecircumstances, it is possible to provide a fourth or polynomial layer asa new layer or in the same planar state. When the organic layer forms aB/G/R layer, a charge accumulation/transfer/read-out site is providedthereunder. When an inorganic layer is used as the electromagnetic waveabsorption/photoelectric conversion site, this inorganic layer alsoserves as the charge accumulation/transfer/read-out site.

In the invention, the following is an especially preferred embodimentamong the devices as described previously.

That is, the preferred embodiment is the case having at least twoelectromagnetic wave absorption/photoelectric conversion sites, with atleast one site thereof being the device (imaging device) according tothe invention.

In addition, the case of a device in which at least two electromagneticwave absorption/photoelectric conversion sites have a stack typestructure of at least two layers is preferable. In addition, the casewhere the upper layer is made of a site capable of absorbing green lightand undergoing photoelectric conversion is preferable.

Furthermore, the case having at least three electromagnetic waveabsorption/photoelectric conversion sites, with at least one sitethereof being the device (imaging device) according to the invention isespecially preferable.

In addition, the case of a device in which the upper layer is made of asite capable of absorbing green light and undergoing photoelectricconversion is preferable. In addition, the case where at least twoelectromagnetic wave absorption/photoelectric conversion sites of thethree sites are made of an inorganic layer (which is preferably formedwithin a silicon substrate) is preferable.

(Electrode)

The electromagnetic wave absorption/photoelectric conversion site madeof an organic layer according to the invention is interposed between onepair of electrodes, and a pixel electrode and a counter electrode areformed, respectively. It is preferable that the lower layer is a pixelelectrode.

It is preferable that the counter electrode extracts a hole from a holetransport photoelectric conversion layer or a hole transport layer. Asthe counter electrode, a metal, an alloy, a metal oxide, an electricallyconducting compound, or a mixture thereof can be used. It is preferablethat the pixel electrode extracts an electron from an electron transportphotoelectric conversion layer or an electron transport layer. The pixelelectrode is selected while taking into consideration adhesion to anadjacent layer such as an electron transport photoelectric conversionlayer and an electron transport layer, electron affinity, ionizationpotential, stability, and the like. Specific examples thereof includeconducting metal oxides such as tin oxide, zinc oxide, indium oxide, andindium tin oxide (ITO); metals such as gold, silver, chromium, andnickel; mixtures or stacks of such a metal and such a conducting metaloxide; inorganic conducting substances such as copper iodide and coppersulfide; organic conducting materials such as polyaniline,polythiophene, and polypyrrole; silicon compounds; and stack materialsthereof with ITO. Of these, conducting metal oxides are preferable; andITO and IZO (indium zinc oxide) are especially preferable in view ofproductivity, high conductivity, transparency, and so on. Though thelayer thickness can be properly selected depending upon the material, ingeneral, it is preferably in the range of 10 nm or more and not morethan 1 μm, more preferably in the range of 30 nm or more and not morethan 500 nm, and further preferably in the range of 50 nm or more andnot more than 300 nm.

In the preparation of the pixel electrode and the counter electrode,various methods are employable depending upon the material. For example,in the case of ITO, the layer is formed by a method such as an electronbeam method, a sputtering method, a resistance heating vapor depositionmethod, a chemical reaction method (for example, a sol-gel method), andcoating of a dispersion of indium tin oxide. In the case of ITO, aUV-ozone treatment, a plasma treatment, or the like can be applied.

In the invention, it is preferable that a transparent electrode layer isprepared in a plasma-free state. By preparing a transparent electrodelayer in a plasma-free state, it is possible to minimize influences ofthe plasma against the substrate and to make photoelectric conversioncharacteristics satisfactory. Here, the term “plasma-free state” means astate that plasma is not generated during the film formation of atransparent electrode layer or that a distance from the plasmageneration source to the substrate is 2 cm or more, preferably 10 cm ormore, and more preferably 20 cm or more and that the plasma whichreaches the substrate is reduced.

Examples of a device in which plasma is not generated during the filmformation of a transparent electrode layer include an electron beamvapor deposition device (EB vapor deposition device) and a pulse laservapor deposition device. With respect to the EB vapor deposition deviceor pulse laser vapor deposition device, devices as described inDevelopments of Transparent Conducting Films, supervised by YutakaSawada (published by CMC Publishing Co., Ltd., 1999); Developments ofTransparent Conducting Films II, supervised by Yutaka Sawada (publishedby CMC Publishing Co., Ltd., 2002); Technologies of TransparentConducting Films, written by Japan Society for the Promotion of Science(published by Ohmsha, Ltd., 1999); and references as added therein canbe used. In the following, the method for achieving film formation of atransparent electrode film using an EB vapor deposition device isreferred to as “EB vapor deposition method”; and the method forachieving film formation of a transparent electrode film using a pulselaser vapor deposition device is referred to as “pulse laser vapordeposition method”.

With respect to the device capable of realizing the state that adistance from the plasma generation source to the substrate is 2 cm ormore and that the plasma which reaches the substrate is reduced(hereinafter referred to as “plasma-free film formation device”), forexample, a counter target type sputtering device and an arc plasma vapordeposition method can be thought. With respect to these matters, devicesas described in Developments of Transparent Conducting Films, supervisedby Yutaka Sawada (published by CMC Publishing Co., Ltd., 1999);Developments of Transparent Conducting Films II, supervised by YutakaSawada (published by CMC Publishing Co., Ltd., 2002); Technologies ofTransparent Conducting Films, written by Japan Society for the Promotionof Science (published by Ohmsha, Ltd., 1999); and references as addedtherein can be used.

The electrode of the organic electromagnetic waveabsorption/photoelectric conversion site according to the invention willbe hereunder described in more detail. The photoelectric conversionlayer as an organic layer is interposed between a pixel electrode layerand a counter electrode layer and can contain an interelectrode materialor the like. The “pixel electrode layer” as referred to herein refers toan electrode layer as prepared above a substrate in which a chargeaccumulation/transfer/read-out site is formed and is usually divided forevery one pixel. This is made for the purpose of obtaining an image byreading out a signal charge which has been converted by thephotoelectric conversion layer on a charge accumulation/transfer/signalread-out circuit substrate for every one pixel.

The “counter electrode layer” as referred to herein has a function todischarge a signal charge having a reversed polarity to a signal chargeby interposing the photoelectric conversion layer together with thepixel electrode layer. Since this discharge of a signal charge is notrequired to be divided among the respective pixels, the counterelectrode layer can be usually made common among the respective pixels.For that reason, the counter electrode layer is sometimes called acommon electrode layer.

The photoelectric conversion layer is positioned between the pixelelectrode layer and the counter electrode layer. The photoelectricconversion function functions by this photoelectric convention layer andthe pixel electrode layer and the counter electrode layer.

As examples of the construction of the photoelectric conversion layerstack, first of all, in the case where one organic layer is stacked on asubstrate, there is enumerated a construction in which a pixel electrodelayer (basically a transparent electrode layer), a photoelectricconversion layer and a counter electrode layer (transparent electrodelayer) are stacked in this order from the substrate. However, it shouldnot be construed that the invention is limited thereto.

In addition, in the case where two organic layers are stacked on asubstrate, there is enumerated a construction in which a pixel electrodelayer (basically a transparent electrode layer), a photoelectricconversion layer, a counter electrode layer (transparent electrodelayer), an interlaminar insulating layer, a pixel electrode layer(basically a transparent electrode layer), a photoelectric conversionlayer, and a counter electrode layer (transparent electrode layer) arestacked in this order from the substrate.

As the material of the transparent electrode layer which constructs thephotoelectric conversion site according to the invention, materialswhich can be subjected to film formation by a plasma-free film formationdevice, EB vapor deposition device or pulse laser vapor depositiondevice. For example, metals, alloys, metal oxides, metal nitrides,metallic borides, organic conducting compounds, and mixtures thereof canbe suitably enumerated. Specific examples thereof include conductingmetal oxides such as tin oxide, zinc oxide, indium oxide, indium zincoxide (IZO), indium tin oxide (ITO), and indium tungsten oxide (IWO);metal nitrides such as titanium nitride; metals such as gold, platinum,silver, chromium, nickel, and aluminum; mixtures or stacks of such ametal and such a conducting metal oxide; inorganic conducting substancessuch as copper iodide and copper sulfide; organic conducting materialssuch as polyaniline, polythiophene, and polypyrrole; and stacks thereofwith ITO. Also, materials as described in detail in Developments ofTransparent Conducting Films, supervised by Yutaka Sawada (published byCMC Publishing Co., Ltd., 1999); Developments of Transparent ConductingFilms II, supervised by Yutaka Sawada (published by CMC Publishing Co.,Ltd., 2002); Technologies of Transparent Conducting Films, written byJapan Society for the Promotion of Science (published by Ohmsha, Ltd.,1999); and references as added therein may be used.

As the material of the transparent electrode layer, any one material ofITO, IZO, SnO₂, ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zincoxide), GZO (gallium-doped zinc oxide), TiO₂, or FTO (fluorine-doped tinoxide) is especially preferable.

A light transmittance of the transparent electrode layer is preferably60% or more, more preferably 80% or more, further preferably 90% ormore, and still further preferably 95% or more at a photoelectricconversion optical absorption peak wavelength of the photoelectricconversion layer to be contained in a photoelectric conversion devicecontaining that transparent electrode layer. Furthermore, with respectto a surface resistance of the transparent electrode layer, itspreferred range varies depending upon whether the transparent electrodelayer is a pixel electrode or a counter electrode, whether the chargeaccumulation/transfer/read-out site is of a CCD structure or a CMOSstructure, and the like. In the case where the transparent electrodelayer is used for a counter electrode and the chargeaccumulation/transfer/read-out site is of a CMOS structure, the surfaceresistance is preferably not more than 10,000Ω/□, and more preferablynot more than 1,000Ω/□. In the case where the transparent electrodelayer is used for a counter electrode and the chargeaccumulation/transfer/read-out site is of a CCD structure, the surfaceresistance is preferably not more than 1,000Ω/□, and more preferably notmore than 100Ω/□. In the case where the transparent electrode layer isused for a pixel electrode, the surface resistance is preferably notmore than 1,000,000Ω/□, and more preferably not more than 100,000Ω/□.

Conditions at the time of film formation of a transparent electrodelayer will be hereunder mentioned. A substrate temperature at the timeof film formation of a transparent electrode layer is preferably nothigher than 500° C., more preferably not higher than 300° C., furtherpreferably not higher than 200° C., and still further preferably nothigher than 150° C. Furthermore, a gas may be introduced during the filmformation of a transparent electrode. Basically, though the gas speciesis not limited, Ar, He, oxygen, nitrogen, and so on can be used.Furthermore, a mixed gas of such gases may be used. In particular, inthe case of an oxide material, since oxygen deficiency often occurs, itis preferred to use oxygen.

(Inorganic Layer)

An inorganic layer as the electromagnetic wave absorption/photoelectricconversion site will be hereunder described. In this case, light whichhas passed through the organic layer as the upper layer is subjected tophotoelectric conversion in the inorganic layer. With respect to theinorganic layer, pn junction or pin junction of crystalline silicon,amorphous silicon, or a chemical semiconductor such as GaAs is generallyemployed. With respect to the stack type structure, a method asdisclosed in U.S. Pat. No. 5,965,875 can be employed. That is, aconstruction in which a light receiving part as stacked by utilizingwavelength dependency of a coefficient of absorption of silicon isformed and color separation is carried out in a depth direction thereof.In this case, since the color separation is carried out with a lightpenetration depth of silicon, a spectrum range as detected in each ofthe stacked light receiving parts becomes broad. However, by using theforegoing organic layer as the upper layer, namely by detecting thelight which has transmitted through the organic layer in the depthdirection of silicon, the color separation is remarkably improved. Inparticular, when a G layer is disposed in the organic layer, since lightwhich has transmitted through the organic layer is B light and R light,only BR light is subjective to separation of light in the depthdirection in silicon so that the color separation is improved. Even inthe case where the organic layer is a B layer or an R layer, by properlyselecting the electromagnetic wave absorption/photoelectric conversionsite of silicon in the depth direction, the color separation isremarkably improved. In the case where the organic layer is made of twolayers, the function as the electromagnetic waveabsorption/photoelectric conversion site of silicon may be brought foronly one color, and preferred color separation can be achieved.

The inorganic layer preferably has a structure in which pluralphotodiodes are superposed for every pixel in a depth direction withinthe semiconductor substrate and a color signal corresponding to a signalcharge as generated in each of the photodiodes by light as absorbed inthe plural photodiodes is read out into the external. It is preferablethat the plural photodiodes contain a first photodiode as provided inthe depth for absorbing B light and at least one second photodiode asprovided in the depth for absorbing R light and are provided with acolor signal read-out circuit for reading out a color signalcorresponding to the foregoing signal charge as generated in each of theforegoing plural photodiodes. According to this construction, it ispossible to carry out color separation without using a color filter.Furthermore, according to circumstances, since light of a negativesensitive component can also be detected, it becomes possible to realizecolor imaging with good color reproducibility. Moreover, in theinvention, it is preferable that a junction part of the foregoing firstphotodiode is formed in a depth of up to about 0.2 μm from thesemiconductor substrate surface and that a junction part of theforegoing second photodiode is formed in a depth of up to about 2 μmfrom the semiconductor substrate surface.

The inorganic layer will be hereunder described in more detail.Preferred examples of the construction of the inorganic layer include aphotoconductive type, a p-n junction type, a Schottky junction type, aPIN junction type, a light receiving device of MSM(metal-semiconductor-metal) type, and a light receiving device ofphototransistor type. In the invention, it is preferred to use a lightreceiving device in which a plural number of a first conducting typeregion and a second conducting type region which is a reversedconducting type to the first conducting type are alternately stackedwithin a single semiconductor substrate and each of the junction planesof the first conducting type and second conducting type regions isformed in a depth suitable for subjecting mainly plural lights of adifferent wavelength region to photo-electric conversion The singlesemiconductor substrate is preferably mono-crystalline silicon, and thecolor separation can be carried out by utilizing absorption wavelengthcharacteristics relying upon the depth direction of the siliconsubstrate.

As the inorganic semiconductor, InGaN based, InAIN based, InAlP based,or InGaAlP based inorganic semiconductors can also be used. The InGaNbased inorganic semiconductor is an inorganic semiconductor as adjustedso as to have a maximum absorption value within a blue wavelength rangeby properly changing the In-containing composition. That is, thecomposition becomes In_(x)Ga_(1-x)N (0<x<1).

Such a compound semiconductor is produced by employing a metal organicchemical vapor deposition method (MOCVD method). With respect to theInAlN based nitride semiconductor using, as a raw material, Al of theGroup 13 similar to Ga, it can be used as a short wavelength lightreceiving part similar to the InGaN based semiconductor. Furthermore,InAlP or InGaAlP lattice-matching with a GaAs substrate can also beused.

The inorganic semiconductor may be of a buried structure. The “buriedstructure” as referred to herein refers to a construction in which theboth ends of a short wavelength light receiving part are covered by asemiconductor different from the short wavelength light receiving part.The semiconductor for covering the both ends is preferably asemiconductor having a band gap wavelength shorter than or equal to ahand gap wavelength of the short wavelength light receiving part.

The organic layer and the inorganic layer may be bound to each other inany form. Furthermore, for the purpose of electrically insulating theorganic layer and the inorganic layer from each other, it is preferredto provide an insulating layer therebetween.

With respect to the junction, npn junction or pnpn junction from thelight incident side is preferable. In particular, the pnpn junction ismore preferable because by providing a p layer on the surface andincreasing a potential of the surface, it is possible to trap a hole asgenerated in the vicinity of the surface and a dark current and reducethe dark current.

In such a photodiode, when an n-type layer, a p-type layer, an n-typelayer and a p-type layer which are successively diffused from the p-typesilicon substrate surface are deeply formed in this order, thepn-junction diode is formed of four layers of pnpn in a depth directionof silicon. With respect to the light which has come into the diode fromthe surface side, the longer the wavelength, the deeper the lightpenetration is. Also, the incident wavelength and the attenuationcoefficient are inherent to silicon. Accordingly, the photodiode isdesigned such that the depth of the pn junction plane covers respectivewavelength bands of visible light. Similarly, a junction diode of threelayers of npn is obtained by forming an n-type layer, a p-type layer andn-type layer in this order. Here, a light signal is extracted from then-type layer, and the p-type layer is connected to a ground wire.

Furthermore, when an extraction electrode is provided in each region anda prescribed reset potential is applied, each region is depleted, andthe capacity of each junction part becomes small unlimitedly. In thisway, it is possible to make the capacity as generated on the junctionplane extremely small.

(Auxiliary Layer)

In the invention, it is preferred to provide an ultraviolet lightabsorption layer and/or an infrared light absorption layer as anuppermost layer of the electromagnetic wave absorption/photoelectricconversion site. The ultraviolet light absorption layer is able to atleast absorb or reflect light of not more than 400 nm and preferably hasan absorptance of 50% or more in a wavelength region of not more than400 nm. The infrared light absorption layer is able to at least absorbor reflect light of 700 nm or more and preferably has an absorptance of50% or more in a wavelength region of 700 nm or more.

Such an ultraviolet light absorption layer or infrared light absorptionlayer can be formed by a conventionally known method. For example, thereis known a method in which a mordant layer made of a hydrophilic highmolecular substance such as gelatin, casein, glue, and polyvinyl alcoholis provided on a substrate and a dye having a desired absorptionwavelength is added to or dyes the mordant layer to form a coloredlayer. In addition, there is known a method of using a colored resinresulting from dispersing a certain kind of coloring material in atransparent resin. For example, it is possible to use a colored resinlayer resulting from mixing a coloring material in a polyamino basedresin as described in JP-A-58-46325, JP-A-60-78401, JP-A-60-184202,JP-A-60-184203, JP-A-60-184204, and JP-A-60-184205. A coloring agentusing a polyamide resin having photosensitivity can also be used.

It is also possible to disperse a coloring material in an aromaticpolyamide resin containing a photosensitive group in the moleculethereof and capable of obtaining a cured layer at not higher than 200°C. as described in JP-B-7-113685 and to use a colored resin having apigment dispersed therein as described in JP-B-7-69486.

In the invention, a dielectric multiple layer is preferably used. Thedielectric multiple layer has sharp wavelength dependency of lighttransmission and is preferably used.

It is preferable that the respective electromagnetic waveabsorption/photoelectric conversion sites are separated by an insulatinglayer. The insulating layer can be formed by using a transparentinsulating material such as glass, polyethylene, polyethyleneterephthalate, polyethersulfone, and polypropylene. Silicon nitride,silicon oxide, and the like are also preferably used. Silicon nitrideprepared by film formation by plasma CVD is preferably used in theinvention because it is high in compactness and good in transparency.

For the purpose of preventing contact with oxygen, moisture, etc., aprotective layer or a sealing layer can be provided, too.

Examples of the protective layer include a diamond thin layer, aninorganic material layer made of a metal oxide, a metal nitride, etc., ahigh molecular layer made of a fluorine resin, poly-p-xylene,polyethylene, a silicone resin, a polystyrene resin, etc., and a layermade of a photocurable resin. Furthermore, it is also possible to covera device portion by glass, a gas-impermeable plastic, a metal, etc. andpackage the device itself by a suitable sealing resin. In this case, itis also possible to make a substance having high water absorptionproperties present in a packaging.

In addition, light collecting efficiency can be improved by forming amicrolens array in the upper part of a light receiving device, andtherefore, such an embodiment is preferable, too.

(Charge Accumulation/Transfer/Read-out Site)

As to the charge accumulation/transfer/read-out site, JP-A-58-103166,JP-A-58-103165, JP-A-2003-332551, and so on can be made hereof byreference. A construction in which an MOS transistor is formed on asemiconductor substrate for every pixel unit or a construction havingCCD as a device can be properly employed. For example, in the case of aphotoelectric conversion device using an MOS transistor, a charge isgenerated in a photoelectric conversion layer by incident light whichhas transmitted through electrodes; the charge runs to the electrodeswithin the photoelectric conversion layer by an electric field asgenerated between the electrodes by applying voltage to the electrodes;and the charge is further transferred to a charge accumulating part ofthe MOS transistor and accumulated in the charge accumulating part. Thecharge as accumulated in the charge accumulating part is transferred toa charge read-out part by switching of the MOS transistor and furtheroutputted as an electric signal. In this way, full-color image signalsare inputted in a solid imaging device including a signal processingpart.

The signal charge can be read out by injecting a fixed amount of biascharge into the accumulation diode (refresh mode) and then accumulatinga fixed amount of the charge (photoelectric conversion mode). The lightreceiving device itself can be used as the accumulation diode, or anaccumulation diode can be separately provided.

The read-out of the signal will be hereunder described in more detail.The read-out of the signal can be carried out by using a usual colorread-out circuit. A signal charge or a signal current which is subjectedto light/electric conversion in the light receiving part is accumulatedin the light receiving part itself or a capacitor as provided. Theaccumulated charge is subjected to selection of a pixel position andread-out by a measure of an MOS type imaging device (so-called CMOSsensor) using an X-Y address system. Besides, as an address selectionsystem, there is enumerated a system in which every pixel issuccessively selected by a multiplexer switch and a digital shiftregister and read out as a signal voltage (or charge) on a common outputline. An imaging device of a two-dimensionally arrayed X-Y addressoperation is known as a CMOS sensor. In this imaging device, a switch asprovided in a pixel connected to an X-Y intersection point is connectedto a vertical shift register, and when the switch is turned on by avoltage from the vertical scanning shift register, signals as read outfrom pixels as provided in the same line is read out on the output linein a column direction. The signals are successively read out from anoutput end through the switch to be driven by a horizontal scanningshift register.

For reading out the output signals, a floating diffusion detector or afloating gate detector can be used. Furthermore, it is possible to seekimprovements of S/N by a measure such as provision of a signalamplification circuit in the pixel portion and correlate doublesampling.

For the signal processing, gamma correction by an ADC circuit,digitalization by an AD transducer, luminance signal processing, andcolor signal processing can be applied. Examples of the color signalprocessing include white balance processing, color separationprocessing, and color matrix processing. In using for an NTSC signal, anRGB signal can be subjected to conversion processing of a YIQ signal.

The charge transfer/read-out site must have a mobility of charge of 100cm²/vol sec or more. This mobility can be obtained by selecting thematerial among semiconductors of the IV group, the III-V group or theII-VI group. Above all, silicon semiconductors (also referred to as “Sisemiconductor”) are preferable because of advancement of microstructurerefinement technology and low costs. As to the charge transfer/chargeread-out system, there are made a number of proposals, and all of themare employable. Above all, a COMS type device or a CCD type device is anespecially preferred system. In addition, in the case of the invention,in many occasions, the CMOS type device is preferable in view ofhigh-speed read-out, pixel addition, partial read-out and consumedelectricity.

(Connection)

Though plural contact sites for connecting the electromagnetic waveabsorption/photoelectric conversion side to the charge transfer/read-outsite may be connected by any metal, a metal selected among copper,aluminum, silver, gold, chromium and tungsten is preferable, and copperis especially preferable. In response to the plural electromagnetic waveabsorption/photoelectric conversion sites, each of the contact sitesmust be placed between the electromagnetic wave absorption/photoelectricconversion site and the charge transfer/read-out site. In the case ofemploying a stacked structure of plural photosensitive units of blue,green and red lights, a blue light extraction electrode and the chargetransfer/read-out site, a green light extraction electrode and thecharge transfer/read-out site, and a red light extraction electrode andthe charge transfer/read-out site must be connected, respectively.

(Process)

The stacked photoelectric conversion device according to the inventioncan be produced according to a so-called known microfabrication processwhich is employed in manufacturing integrated circuits and the like.Basically, this process is concerned with a repeated operation ofpattern exposure with active light, electron beams, etc. (for example,i- or g-bright line of mercury, excimer laser, X-rays, and electronbeams), pattern formation by development and/or burning, alignment ofdevice forming materials (for example, coating, vapor deposition,sputtering, and CV), and removal of the materials in a non-pattern area(for example, heat treatment and dissolution treatment).

(Utility)

A chip size of the device can be selected among a brownie size, a 135size, an APS size, a 1/1.8-inch size, and a smaller size. A pixel sizeof the stacked photoelectric conversion device according to theinvention is expressed by a circle-corresponding diameter which iscorresponding to a maximum area in the plural electromagneticabsorption/photoelectric conversion sites. Though the pixel size is notlimited, it is preferably from 2 to 20 microns, more preferably from 2to 10 microns, and especially preferably from 3 to 8 microns.

When the pixel size exceeds 20 microns, a resolving power is lowered,whereas when the pixel size is smaller than 2 microns, the resolvingpower is also lowered due to radio interference between the sizes.

The stacked photoelectric conversion device according to the inventioncan be utilized for a digital still camera. Also, it is preferable thatthe photoelectric conversion device according to the invention is usedfor a TV camera. Besides, the photoelectric conversion device accordingto the invention can be utilized for a digital video camera, a monitorcamera (in, for example, office buildings, parking lots, unmannedloan-application systems in financial institution, shopping centers,convenience stores, outlet malls, department stores, pachinko parlors,karaoke boxes, game centers, and hospitals), other various sensors (forexample, TV door intercoms, individual authentication sensors, sensorsfor factory automation, robots for household use, industrial robots, andpiping examination systems), medical sensors (for example, endoscopesand fundus cameras), videoconference systems, television telephones,camera-equipped mobile phones, automobile safety running systems (forexample, back guide monitors, collision prediction systems, andlane-keeping systems), and sensors for video game.

Above all, the photoelectric conversion device according to theinvention is suitable for use of a television camera. The reason forthis resides in the matter that since it does not require a colordecomposition optical system, it is able to achieve miniaturization andweight reduction of the television camera. Furthermore, since thephotoelectric conversion device according to the invention has highsensitivity and high resolving power, it is especially preferable for atelevision camera for high-definition broadcast. In this case, the term“television camera for high-definition broadcast” as referred to hereinincludes a camera for digital high-definition broadcast.

In addition, the photoelectric conversion device according to theinvention is preferable because an optical low pass filter can beomitted and higher sensitivity and higher resolving power can beexpected.

In addition, in the photoelectric conversion device according to theinvention, not only the thickness can be made thin, but also a colordecomposition optical system is not required. Therefore, with respect toshooting scenes in which a different sensitivity is required, such as“circumstances with a different brightness such as daytime andnighttime” and “immobile subject and mobile subject” and other shootingscenes in which requirements for spectral sensitivity or colorreproducibility differ, various needs for shooting can be satisfied by asingle camera by exchanging the photoelectric conversion deviceaccording to the invention and performing shooting. At the same time, itis not required to carry plural cameras. Thus, a load of a person whowishes to take a shot is reduced. As a photoelectric conversion devicewhich is subjective to the exchange, in addition to the foregoing,exchangeable photoelectric conversion devices for purposes of infraredlight shooting, black-and-white shooting, and change of a dynamic rangecan be prepared.

The TV camera according to the invention can be prepared by referring toa description in Chapter 2 of Design Technologies of Television Camera,edited by the Institute of Image Information and Television Engineers(Aug. 20, 1999, published by Corona Publishing Co., Ltd., ISBN4-339-00714-5) and, for example, replacing a color decomposition opticalsystem and an imaging device as a basic construction of a televisioncamera as shown in FIG. 2.1 thereof by the photoelectric conversiondevice according to the invention.

By aligning the foregoing stacked light receiving device, it can beutilized not only as an imaging device but also as an optical sensorsuch as biosensors and chemical sensors or a color light receivingdevice in a single body.

(Preferred Photoelectric Conversion Device According to the Invention)

A preferred photoelectric conversion device according to the inventionwill be hereunder described with reference to FIG. 2. A numeral 13 is asilicon mono-crystal substrate and serves as both an electromagneticwave absorption/photoelectric conversion site of B light and R light anda charge accumulation of charge as generated by photoelectricconversion/transfer/and read-out site. Usually, a p-type siliconsubstrate is used. Numerals 21, 22 and 23 represent an n layer, a player and an n layer, respectively as provided in the silicon substrate.The n layer 21 is an accumulation part of a signal charge of R light andaccumulates a signal charge of R light which has been subjected tophotoelectric conversion by pn junction. The accumulated charge isconnected to a signal read-out pad 27 by a metal wiring 19 via atransistor 26. The n layer 23 is an accumulation part of a signal chargeof B light and accumulates a signal charge of B light which has beensubjected to photoelectric conversion by pn junction. The accumulatedcharge is connected to the signal read-out pad 27 by the metal wiring 19via a transistor similar to the transistor 26. Here, though the p layer,the n layer, the transistor, the metal wiring, and the like areschematically shown, each of them is properly selected among optimumstructures and so on as described previously in detail. Since the Blight and the R light are divided depending upon the depth of thesilicon substrate, it is important to select the depth of the pnjunction, etc. from the silicon substrate, the dope concentration and soon. A numeral 12 is a layer containing a metal wiring and is a layercontaining, as a major component, silicon oxide, silicon nitride, etc.It is preferable that the thickness of the layer 12 is thin as far aspossible. The thickness of the layer 12 is not more than 5 μm,preferably not more than 3 μm, and further preferably not more than 2μm. A numeral 11 is also a layer containing, as a major component,silicon oxide, silicon nitride, etc. The layers 11 and 12 are eachprovided with a plug for sending a signal charge of G light to thesilicon substrate. The plugs are connected to each other between thelayers 11 and 12 by a pad 16. As the plug, one containing, as a majorcomponent, tungsten is preferably used. As the pad, one containing, as amajor component, aluminum is preferably used. It is preferable that abarrier layer including the foregoing metal wiring is provided. Thesignal charge of G light which is sent via plugs 15 is accumulated in alayer 25 in the silicon substrate. The n layer 25 is separated by a player 24. The accumulated charge is connected to the signal read-out pad27 by the metal wiring 19 via the transistor similar to the transistor26. Since the photoelectric conversion by the pn junction by the layers24 and 25 becomes a noise, a light shielding layer 17 is provided in thelayer 11. As the light shielding layer, one containing, as a majorcomponent, tungsten, aluminum, etc. is usually used. It is preferablethat the thickness of the layer 12 is thin as far as possible. Thethickness of the layer 12 is not more than 3 μm, preferably not morethan 2 μm, and further preferably not more than 1 μm. It is preferablethat the signal read-out pad 27 is provided for every signal of the B, Gand R signals. The foregoing process can be achieved by a conventionallyknown process, a so-called CMOS process.

The electromagnetic wave absorption/photoelectric conversion site of Glight is shown by numerals 6, 7, 8, 9, 10 and 14. The numerals 6 and 14are each a transparent electrode and are corresponding to a counterelectrode and a pixel electrode, respectively. Though the pixelelectrode 14 is a transparent electrode, for the purpose of enhancingthe electric connection with the plug 15, in many cases, a site made ofaluminum, molybdenum, etc. is required in the connecting part. Thesetransparent electrodes are biased through a wiring from a connectionelectrode 18 and a counter electrode pad 20. A structure in which anelectron can be accumulated in the layer 25 by positively biasing thepixel electrode 14 against the transparent counter electrode 6 ispreferable. In this case, the numeral 7 is an electron blocking layer;the numeral 8 is a p layer; the numeral 9 is an n layer; and the numeral10 is a hole blocking layer. Here, a representative layer constructionof the organic layer was shown. The thickness of the organic layer madeof the layers 7, 8, 9 and 10 is preferably not more than 0.5 μm, morepreferably not more than 0.3 μm, and especially preferably not more than0.2 μm in total. A thickness of each of the transparent counterelectrode 6 and the transparent pixel electrode 14 is especiallypreferably not more than 0.2 μm. Numerals 3, 4 and 5 are each aprotective layer containing, as a major component, silicon nitride, etc.By these protective layers, it becomes easy to achieve a manufacturingprocess of layers containing the organic layer. In particular, theselayers are able to reduce damages against the organic layer at the timeof resist pattern preparation and etching during the preparation of theconnection electrode 18 and the like. Furthermore, in order to avoid theresist pattern preparation, the etching and the like, it is alsopossible to achieve the production using a mask. So far as the foregoingconditions are met, the thickness of each of the protective layers 3, 4and 5 is preferably not more than 0.5 μm. The numeral 3 is a protectivelayer of the connection electrode 18. A numeral 2 is an infraredlight-cut dielectric multiple layer. A numeral 1 is an antireflectionlayer. A total thickness of the layers 1, 2 and 3 is preferably not morethan 1 μm.

The photoelectric conversion device as described previously by FIG. 2 isconstructed of one pixel for each of the B pixel and the R pixel vs.four pixels for the G pixel. The photoelectric conversion device may beconstructed of one pixel for each of the B pixel and the R pixel vs. onepixel for the G pixel; may be constructed of one pixel for each of the Bpixel and the R pixel vs. three pixel for the G pixel; and may beconstructed of one pixel for each of the B pixel and the R pixel vs. twopixels for the G pixel. In addition, the photoelectric conversion devicemay be constructed of an arbitrary combination. While preferredembodiments of the invention have been described, it should not beconstrued that the invention is limited thereto.

EXAMPLES

Examples and Embodiments of the invention will be hereunder described,but it should not be construed that the invention is limited thereto.

Example 1

A rinsed ITO substrate was placed in a vapor deposition device andsubjected to vapor deposition with the following Compound (S-1) in athickness of 30 nm. Compound (3) of the invention was then subjected tovapor deposition in a thickness of 30 nm thereon, thereby preparing anorganic pn stack type photoelectric conversion layer. Next, a patternedmask (with a light receiving area of 2 mm×2 mm) was placed on theorganic thin layer and subjected to vapor deposition with aluminum in athickness of 100 nm within the vapor deposition device, and a dryingagent was subsequently charged, thereby sealing the device. There wasthus prepared a photoelectric conversion device (Device No. 101). Acomparative photoelectric conversion device (Device No. 102) wasprepared by replacing the Compound (3) of the invention by the followingCompound (S-2).

Next, the respective devices were evaluated in the following manners.

With respect to Device No. 101, the case where a bias of 5 V was appliedwhile making the ITO side minus and making the aluminum electrode sideplus and the case where a bias was not applied were evaluated. Withrespect to Device No. 102, the case where a bias was not applied wasevaluated.

Using a solar module evaluation system manufactured by Optel, thewavelength dependency of external quantum yield was evaluated. Whensimulation was carried out by using the resulting photoelectricconversion spectrum to form a device for G, the spectral characteristicwas evaluated. A level of the color reproducibility (spectralcharacteristic) was expressed by “Good” or “Bad”. The results obtainedare shown in Table 1.

In comparison with Device No. 102 for comparison, Device No. 101 of thisExample exhibited a high external quantum yield in the case where a biaswas not applied. Furthermore, in the case where a bias was applied,Device No. 101 exhibited a higher external quantum yield than that inthe case where a bias was not applied. In addition, Device No. 101exhibited an excellent spectral characteristic in a green region ascompared with Device No. 102 for comparison.

TABLE 1 p-Type n-Type Eternal quantum Spectral Device No. Bias compoundcompound yield ¹⁾ characteristic Remark 101 5 V (S-1) (3) 30%  GoodInvention 101 Not applied (S-1) (3) 7% Good Invention 102 Not applied(S-1) (S-2) 1% Bad Comparison ¹⁾ Efficiency at absorption maximumwavelength

Example 2

A rinsed ITO substrate was placed in a vapor deposition device andsubjected to vapor deposition with Compound (3) of the invention in athickness of 50 nm. The following Compound (S-3) was then subjected tovapor deposition in a thickness of 50 nm thereon, thereby preparing anorganic pn stack type photoelectric conversion layer. Next, a patternedmask (with a light receiving area of 2 mm×2 mm) was placed on theorganic thin layer and subjected to vapor deposition with aluminum in athickness of 100 nm within the vapor deposition device, and a dryingagent was subsequently charged, thereby sealing the device. There wasthus prepared a photoelectric conversion device (Device No. 103).

Next, this device was evaluated in the following manners.

With respect to this device, the case where a bias of 10 V was appliedwhile making the ITO side plus and making the aluminum electrode sideminus.

Using a solar module evaluation system manufactured by Optel, thewavelength dependency of external quantum yield was evaluated. Whensimulation was carried out by using the resulting photoelectricconversion spectrum to form a device for G, the spectral characteristicwas evaluated. A level of the color reproducibility (spectralcharacteristic) was expressed by “Good” or “Bad”. The results obtainedare shown in Table 2.

In the case where a bias was applied, Device No. 103 exhibited a highexternal quantum yield. Furthermore, this device exhibited an excellentspectral characteristic in a green region.

TABLE 2 p-Type n-Type Eternal quantum Spectral Device No. Bias compoundcompound yield ¹⁾ characteristic Remark 103 10 V (S-3) (3) 22% GoodInvention ¹⁾ Efficiency at absorption maximum wavelength

Example 3

A rinsed ITO substrate was placed in a vapor deposition device andsubjected to vapor deposition with the following Compound (B-1) in athickness of 20 nm. Compound (3) of the invention was then subjected tovapor deposition in a thickness of 50 nm thereon; Compound (S-3) wasfurther subjected to vapor deposition in a thickness of 50 nm thereon;and the following Compound (B-2) was still further subjected to vapordeposition in a thickness of 50 nm thereon, thereby preparing an organicpn stack type photoelectric conversion layer. Next, a patterned mask(with a light receiving area of 2 mm×2 mm) was placed on the organicthin layer and subjected to vapor deposition with aluminum in athickness of 100 nm within the vapor deposition device, and a dryingagent was subsequently charged, thereby sealing the device. There wasthus prepared a photoelectric conversion device (Device No. 104).

Furthermore, a rinsed ITO substrate was placed in a vapor depositiondevice and subjected to vapor deposition with Compound (B-1) in athickness of 20 nm. Compound (3) of the invention was then subjected tovapor deposition in a thickness of 5 nm thereon; and Compound (S-3) wasfurther subjected to vapor deposition in a thickness of 5 nm thereon.Additionally, Compound (3) and Compound (S-3) were alternately subjectedto vapor deposition repeatedly 9 times in a thickness of 5 nm,respectively. Compound (B-2) was then subjected to vapor deposition in athickness of 50 nm, thereby preparing an organic pn stack typephotoelectric conversion layer. Next, a patterned mask (with a lightreceiving area of 2 mm×2 mm) was placed on the organic thin layer andsubjected to vapor deposition with aluminum in a thickness of 100 nmwithin the vapor deposition device, and a drying agent was subsequentlycharged, thereby sealing the device. There was thus prepared aphotoelectric conversion device (Device No. 105).

Next, the respective devices were evaluated in the following manners.

With respect to each of the devices, the case where a bias of 10 V wasapplied while making the ITO side plus and making the aluminum electrodeside minus.

Using a solar module evaluation system manufactured by Optel, thewavelength dependency of external quantum yield was evaluated. Whensimulation was carried out by using the resulting photoelectricconversion spectrum to form a device for G, the spectral characteristicwas evaluated. A level of the color reproducibility (spectralcharacteristic) was expressed by “Good” or “Bad”. The results obtainedare shown in Table 3.

In the case where a bias was applied, Device Nos. 104 and 105 of thisExample exhibited a high external quantum yield. Furthermore, thesedevices exhibited an excellent spectral characteristic in a greenregion.

Incidentally, Device No. 105 of a tandem stack type exhibited anespecially high external quantum yield.

TABLE 3 p-Type n-Type Eternal quantum Spectral Device No. Bias compoundcompound yield ¹⁾ characteristic Remark 104 10 V (S-3) (3) 18% GoodInvention 105 10 V (S-3) (3) 21% Good Invention ¹⁾ Efficiency atabsorption maximum wavelength

Example 4

By using each of the devices of Examples 1, 2 and 3 of the invention inthe G layer as shown in FIG. 1, it is possible to prepare a colorimaging device exhibiting excellent color separation.

By using each of the photoelectric conversion sites of Examples 1, 2 and3 which are capable of absorbing G light in the portions 8 and 9 of thephotoelectric conversion site as shown in FIG. 2, it is possible toprepare a color imaging device exhibiting excellent color separation.

This application is based on Japanese Patent application JP 2005-162613,filed Jun. 2, 2005, the entire content of which is hereby incorporatedby reference, the same as if set forth at length.

1. A photoelectric conversion layer comprising a p-type semiconductorlayer containing a p-type semiconductor and an n-type semiconductorlayer containing an n-type semiconductor, wherein at least one of thep-type semiconductor layer and the n-type semiconductor layer consistsof a compound represented by the following formula (I), and the layercontaining a compound represented by formula (I) in the photoelectricconversion layer has a thickness of from 30 nm to 300 nm:

wherein V₁ and V₂ each independently represents a hydrogen atom or asubstituent selected from the group consisting of a halogen atom, analkyl group, a cycloalkyl group, a bicycloalkyl group, a tricycloalkylgroup, an alkenyl group, a cycloalkenyl group, a bicycloalkenyl group,an alkynyl group, an aryl group, a heterocyclic group, a cyano group, ahydroxyl group, a nitro group, a carboxyl group, an alkoxy group, anaryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxygroup, a carbamoyloxy group, an alkoxycarbonyloxy group, anaryloxy-carbonyloxy group, an amino group, an anilino group, an ammoniogroup, an acylamino group, an aminocarbonylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfamoylamino group, an alkyl- or arylsulfonylamino group, a mercaptogroup, an alkylthio group, an arylthio group, a heterocyclic thio group,a sulfamoyl group, a sulfo group, an alkyl- or arylsulfinyl group, analkyl- or arylsulfonyl group, an acyl group, an aryloxycarbonyl group,an alkoxycarbonyl group, a carbamoyl group, an aryl or heterocyclic azogroup, an imide group, a phosphino group, a phosphinyl group, aphosphinyloxy group, a phosphinylamino group, a phosphono group, a silylgroup, a hydrazino group, a ureido group, a boronic acid group, aphosphato group, and a sulfato group; and wherein V₃ and V₄ eachindependently represents a hydrogen atom or a substituent selected fromthe group consisting of a halogen atom, an alkyl group, a cycloalkylgroup, a bicycloalkyl group, a tricycloalkyl group, an alkynyl group, anaryl group, a heterocyclic group, a cyano group, a hydroxyl group, anitro group, a carboxyl group, an alkoxy group, an aryloxy group, asilyloxy group, a heterocyclic oxy group, an acyloxy group, acarbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxygroup, an amino group, an anilino group, an ammonio group, an acylaminogroup, an aminocarbonylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfamoylamino group, an alkyl- orarylsulfonylamino group, a mercapto group, an alkylthio group, anarylthio group, a heterocyclic thio group, a sulfamoyl group, a sulfogroup, an alkyl- or arylsulfinyl group, an alkyl- or arylsulfonyl group,an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, acarbamoyl group, an imide group, a phosphino group, a phosphinyl group,a phosphinyloxy group, a phosphinylamino group, a phosphono group, asilyl group, a hydrazino group, a ureido group, a boronic acid group, aphosphato group, and a sulfato group.
 2. The photoelectric conversionlayer according to claim 1, further comprising a bulk heterojunctionstructure layer provided as an interlayer between the p-typesemiconductor layer and the n-type semiconductor layer, wherein the bulkheterojunction structure layer contains a second p-type semiconductorand an second n-type semiconductor.
 3. The photoelectric conversionlayer according to claim 1, which has a structure having two or morestructures of a pn junction layer including the p-type semiconductorlayer and the n-type semiconductor layer.
 4. The photoelectricconversion layer according to claim 1, wherein the p-type semiconductoris an organic semiconductor and the n-type semiconductor is an organicsemiconductor.
 5. The photoelectric conversion layer according to claim1, wherein the p-type semiconductor or the n-type semiconductor in anincident light side is colorless.
 6. A photoelectric conversion devicecomprising the photoelectric conversion layer according to claim
 1. 7.An imaging device comprising the photoelectric conversion deviceaccording to claim
 6. 8. A photoelectric conversion device comprising apair of electrodes and the photoelectric conversion layer according toclaim 1 provided between the pair of electrodes.
 9. An imaging devicecomprising two or more stacked photoelectric conversion layers, whereinat least one of the photoelectric conversion layers is the photoelectricconversion layer according to claim
 1. 10. The imaging device accordingto claim 9, wherein the imaging device comprises three or morephotoelectric conversion layers including a blue photoelectricconversion layer, a green photoelectric conversion layer and a redphotoelectric conversion layer.
 11. The imaging device according toclaim 10, wherein spectral absorption maximum values of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer are in a range of from 400 nmto 500 nm, in a range of from 500 nm to 600 nm, and in a range of from600 nm to 700 nm, respectively.
 12. The imaging device according toclaim 10, wherein spectral sensitivity maximum values of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer are in a range of from 400 nmto 500 nm, in a range of from 500 nm to 600 nm, and in a range of from600 nm to 700 nm, respectively.
 13. The imaging device according toclaim 10, wherein a gap between a shortest wavelength and a longestwavelength exhibiting 50% of the spectral maximum absorption of each ofthe blue photoelectric conversion layer, the green photo-electricconversion layer and the red photo-electric conversion layer is 120 nmor less.
 14. The imaging device according to claim 10, wherein a gapbetween a shortest wavelength and a longest wavelength exhibiting 50% ofthe spectral maximum sensitivity of each of the blue photoelectricconversion layer, the green photoelectric conversion layer and the redphotoelectric conversion layer is 120 nm or less.
 15. The imaging deviceaccording to claim 10, wherein a gap between a shortest wavelength and alongest wavelength exhibiting 80% of the spectral maximum absorption ofeach of the blue photoelectric conversion layer, the green photoelectricconversion layer and the red photoelectric conversion layer is from 20nm to 100 nm.
 16. The imaging device according to claim 10, wherein agap between a shortest wavelength and a longest wavelength exhibiting80% of the spectral maximum sensitivity of each of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer is from 20 nm to 100 nm. 17.The imaging device according to claim 10, wherein a gap between ashortest wavelength and a longest wavelength exhibiting 20% of thespectral maximum absorption of each of the blue photoelectric conversionlayer, the green photoelectric conversion layer and the redphotoelectric conversion layer is 180 nm or less.
 18. The imaging deviceaccording to claim 10, wherein a gap between a shortest wavelength and alongest wavelength exhibiting 20% of the spectral maximum sensitivity ofeach of the blue photoelectric conversion layer, the green photoelectricconversion layer and the red photoelectric conversion layer is 180 nm orless.
 19. The imaging device according to claim 10, wherein a longestwavelength exhibiting 50% of the spectral maximum absorption of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer is from 460 nm to 510 nm,from 560 nm to 610 nm and from 640 nm to 730 nm, respectively.
 20. Theimaging device according to claim 10, wherein a longest wavelengthexhibiting 50% of the spectral maximum sensitivity of the bluephotoelectric conversion layer, the green photoelectric conversion layerand the red photoelectric conversion layer is from 460 nm to 510 nm,from 560 nm to 610 nm and from 640 nm to 730 nm, respectively.
 21. Animaging device including at least two electromagnetic waveabsorption/photoelectric conversion sites, at least one of the sitescomprising the photoelectric conversion layer according to claim
 1. 22.The imaging device according to claim 21, wherein the at least twoelectromagnetic wave absorption/photoelectric conversion sites have astack type structure of at least two layers.
 23. The imaging deviceaccording to claim 22, wherein an upper layer of the imaging devicecomprises a site capable of absorbing green light and undergoingphotoelectric conversion.
 24. An imaging device including at least threeelectromagnetic wave absorption/photoelectric conversion sites, at leastone of the sites comprising the photoelectric conversion layer accordingto claim
 1. 25. The imaging device according to claim 24, wherein anupper layer of the imaging device comprises a site capable of absorbinggreen light and undergoing photoelectric conversion.
 26. The imagedevice according to claim 24, wherein at least two of theelectromagnetic wave absorption/photoelectric conversion sites comprisean inorganic layer.
 27. The imaging device according to claim 26,wherein at least two of the electromagnetic waveabsorption/photoelectric conversion sites are provided within a siliconsubstrate.
 28. A method comprising applying an electric field of from10⁻² V/cm to 1×10¹⁰ V/cm to the photoelectric conversion layer accordingto claim 1.